diff --git a/core/src/com/unciv/logic/GameInfo.kt b/core/src/com/unciv/logic/GameInfo.kt
index 5d916696ee..b35c04cffe 100644
--- a/core/src/com/unciv/logic/GameInfo.kt
+++ b/core/src/com/unciv/logic/GameInfo.kt
@@ -354,8 +354,7 @@ class GameInfo {
                 tile.terrainFeatures.remove(terrainFeature)
             if (tile.resource != null && !ruleSet.tileResources.containsKey(tile.resource!!))
                 tile.resource = null
-            if (tile.improvement != null && !ruleSet.tileImprovements.containsKey(tile.improvement!!)
-                    && !tile.improvement!!.startsWith("StartingLocation ")) // To not remove the starting locations in GameStarter.startNewGame()
+            if (tile.improvement != null && !ruleSet.tileImprovements.containsKey(tile.improvement!!))
                 tile.improvement = null
 
             for (unit in tile.getUnits()) {
diff --git a/core/src/com/unciv/logic/GameStarter.kt b/core/src/com/unciv/logic/GameStarter.kt
index 414b46268a..b14d93b405 100644
--- a/core/src/com/unciv/logic/GameStarter.kt
+++ b/core/src/com/unciv/logic/GameStarter.kt
@@ -20,62 +20,87 @@ import kotlin.collections.HashMap
 import kotlin.math.max
 
 object GameStarter {
+    // temporary instrumentation while tuning/debugging
+    private const val consoleOutput = true
+    private const val consoleTimings = true
 
     fun startNewGame(gameSetupInfo: GameSetupInfo): GameInfo {
+        if (consoleOutput || consoleTimings)
+            println("\nGameStarter run with parameters ${gameSetupInfo.gameParameters}, map ${gameSetupInfo.mapParameters}")
+
         val gameInfo = GameInfo()
+        lateinit var tileMap: TileMap
 
         gameInfo.gameParameters = gameSetupInfo.gameParameters
         val ruleset = RulesetCache.getComplexRuleset(gameInfo.gameParameters.mods)
 
-        if (gameSetupInfo.mapParameters.name != "") {
-            gameInfo.tileMap = MapSaver.loadMap(gameSetupInfo.mapFile!!)
+        if (gameSetupInfo.mapParameters.name != "") runAndMeasure("loadMap") {
+            tileMap = MapSaver.loadMap(gameSetupInfo.mapFile!!)
             // Don't override the map parameters - this can include if we world wrap or not!
-        } else {
-            gameInfo.tileMap = MapGenerator(ruleset).generateMap(gameSetupInfo.mapParameters)
-            gameInfo.tileMap.mapParameters = gameSetupInfo.mapParameters
+        } else runAndMeasure("generateMap") {
+            tileMap = MapGenerator(ruleset).generateMap(gameSetupInfo.mapParameters)
+            tileMap.mapParameters = gameSetupInfo.mapParameters
         }
 
+        runAndMeasure("addCivilizations") {
+            gameInfo.tileMap = tileMap
+            tileMap.gameInfo = gameInfo // need to set this transient before placing units in the map
+            addCivilizations(gameSetupInfo.gameParameters, gameInfo, ruleset) // this is before gameInfo.setTransients, so gameInfo doesn't yet have the gameBasics
+        }
 
-        gameInfo.tileMap.gameInfo = gameInfo // need to set this transient before placing units in the map
-        addCivilizations(gameSetupInfo.gameParameters, gameInfo, ruleset) // this is before gameInfo.setTransients, so gameInfo doesn't yet have the gameBasics
+        runAndMeasure("Remove units") {
+            // Remove units for civs that aren't in this game
+            for (tile in tileMap.values)
+                for (unit in tile.getUnits())
+                    if (gameInfo.civilizations.none { it.civName == unit.owner }) {
+                        unit.currentTile = tile
+                        unit.setTransients(ruleset)
+                        unit.removeFromTile()
+                    }
+        }
 
-        // Remove units for civs that aren't in this game
-        for (tile in gameInfo.tileMap.values)
-            for (unit in tile.getUnits())
-                if (gameInfo.civilizations.none { it.civName == unit.owner }) {
-                    unit.currentTile = tile
-                    unit.setTransients(ruleset)
-                    unit.removeFromTile()
-                }
+        runAndMeasure("setTransients") {
+            tileMap.setTransients(ruleset) // if we're starting from a map with pre-placed units, they need the civs to exist first
+            tileMap.setStartingLocationsTransients()
 
-        gameInfo.tileMap.setTransients(ruleset) // if we're starting from a map with preplaced units, they need the civs to exist first
+            gameInfo.difficulty = gameSetupInfo.gameParameters.difficulty
 
-        gameInfo.difficulty = gameSetupInfo.gameParameters.difficulty
+            gameInfo.setTransients() // needs to be before placeBarbarianUnit because it depends on the tilemap having its gameInfo set
+        }
 
+        runAndMeasure("Techs and Stats") {
+            addCivTechs(gameInfo, ruleset, gameSetupInfo)
 
-        gameInfo.setTransients() // needs to be before placeBarbarianUnit because it depends on the tilemap having its gameinfo set
+            addCivStats(gameInfo)
+        }
 
-        addCivTechs(gameInfo, ruleset, gameSetupInfo)
-        
-        addCivStats(gameInfo)
-
-        // and only now do we add units for everyone, because otherwise both the gameInfo.setTransients() and the placeUnit will both add the unit to the civ's unit list!
-        addCivStartingUnits(gameInfo)
+        runAndMeasure("addCivStartingUnits") {
+            // and only now do we add units for everyone, because otherwise both the gameInfo.setTransients() and the placeUnit will both add the unit to the civ's unit list!
+            addCivStartingUnits(gameInfo)
+        }
 
         // remove starting locations once we're done
-        for (tile in gameInfo.tileMap.values) {
-            if (tile.improvement != null && tile.improvement!!.startsWith("StartingLocation "))
-                tile.improvement = null
-            // set max starting movement for units loaded from map
+        tileMap.clearStartingLocations()
+
+        // set max starting movement for units loaded from map
+        for (tile in tileMap.values) {
             for (unit in tile.getUnits()) unit.currentMovement = unit.getMaxMovement().toFloat()
         }
-        
+
         // This triggers the one-time greeting from Nation.startIntroPart1/2
         addPlayerIntros(gameInfo)
 
         return gameInfo
     }
 
+    private fun runAndMeasure(text: String, action: ()->Unit) {
+        if (!consoleTimings) return action()
+        val startNanos = System.nanoTime()
+        action()
+        val delta = System.nanoTime() - startNanos
+        println("GameStarter.$text took ${delta/1000000L}.${(delta/10000L).rem(100)}ms")
+    }
+
     private fun addPlayerIntros(gameInfo: GameInfo) {
         gameInfo.civilizations.filter {
             // isNotEmpty should also exclude a spectator
@@ -138,6 +163,8 @@ object GameStarter {
         availableCivNames.addAll(ruleset.nations.filter { it.value.isMajorCiv() }.keys.shuffled())
         availableCivNames.removeAll(newGameParameters.players.map { it.chosenCiv })
         availableCivNames.remove(Constants.barbarians)
+        
+        val startingTechs = ruleset.technologies.values.filter { it.uniques.contains("Starting tech") }
 
         if (!newGameParameters.noBarbarians && ruleset.nations.containsKey(Constants.barbarians)) {
             val barbarianCivilization = CivilizationInfo(Constants.barbarians)
@@ -149,44 +176,36 @@ object GameStarter {
             else availableCivNames.pop()
 
             val playerCiv = CivilizationInfo(nationName)
-            for (tech in ruleset.technologies.values.filter { it.uniques.contains("Starting tech") })
+            for (tech in startingTechs)
                 playerCiv.tech.techsResearched.add(tech.name) // can't be .addTechnology because the civInfo isn't assigned yet
             playerCiv.playerType = player.playerType
             playerCiv.playerId = player.playerId
             gameInfo.civilizations.add(playerCiv)
         }
 
-        val cityStatesWithStartingLocations =
-                gameInfo.tileMap.values
-                        .filter { it.improvement != null && it.improvement!!.startsWith("StartingLocation ") }
-                        .map { it.improvement!!.replace("StartingLocation ", "") }
+        val civNamesWithStartingLocations = gameInfo.tileMap.startingLocationsByNation.keys
 
         val availableCityStatesNames = Stack<String>()
         // since we shuffle and then order by, we end up with all the City-States with starting tiles first in a random order,
         //   and then all the other City-States in a random order! Because the sortedBy function is stable!
         availableCityStatesNames.addAll(ruleset.nations.filter { it.value.isCityState() }.keys
-                .shuffled().sortedByDescending { it in cityStatesWithStartingLocations })
+                .shuffled().sortedByDescending { it in civNamesWithStartingLocations })
 
-        val unusedMercantileResources = ruleset.tileResources.values.filter { it.unique == "Can only be created by Mercantile City-States" }.toMutableList()
+        val allMercantileResources = ruleset.tileResources.values.filter { it.unique == "Can only be created by Mercantile City-States" }.map { it.name }
+        val unusedMercantileResources = Stack<String>()
+        unusedMercantileResources.addAll(allMercantileResources.shuffled())
 
         for (cityStateName in availableCityStatesNames.take(newGameParameters.numberOfCityStates)) {
             val civ = CivilizationInfo(cityStateName)
             civ.cityStatePersonality = CityStatePersonality.values().random()
-            if (ruleset.nations[cityStateName]?.cityStateType == CityStateType.Mercantile) {
-                if (!ruleset.tileResources.values.any { it.unique == "Can only be created by Mercantile City-States" }) {
-                    civ.cityStateResource = null
-                } else if (unusedMercantileResources.isNotEmpty()) {
-                    // First pick an unused luxury if possible
-                    val unusedResource = unusedMercantileResources.random()
-                    civ.cityStateResource = unusedResource.name
-                    unusedMercantileResources.remove(unusedResource)
-                } else {
-                    // Then random
-                    civ.cityStateResource = ruleset.tileResources.values.filter { it.unique == "Can only be created by Mercantile City-States" }.random().name
-                }
+            civ.cityStateResource = when {
+                ruleset.nations[cityStateName]?.cityStateType != CityStateType.Mercantile -> null
+                allMercantileResources.isEmpty() -> null
+                unusedMercantileResources.empty() -> allMercantileResources.random()  // When unused luxuries exhausted, random
+                else -> unusedMercantileResources.pop()  // First pick an unused luxury if possible
             }
             gameInfo.civilizations.add(civ)
-            for (tech in ruleset.technologies.values.filter { it.uniques.contains("Starting tech") })
+            for (tech in startingTechs)
                 civ.tech.techsResearched.add(tech.name) // can't be .addTechnology because the civInfo isn't assigned yet
         }
     }
@@ -194,38 +213,35 @@ object GameStarter {
     private fun addCivStartingUnits(gameInfo: GameInfo) {
 
         val ruleSet = gameInfo.ruleSet
+        val tileMap = gameInfo.tileMap
         val startingEra = gameInfo.gameParameters.startingEra
         var startingUnits: MutableList<String>
         var eraUnitReplacement: String
 
-        val startScores = HashMap<TileInfo, Float>()
-        for (tile in gameInfo.tileMap.values) {
+        val startScores = HashMap<TileInfo, Float>(tileMap.values.size)
+        for (tile in tileMap.values) {
             startScores[tile] = tile.getTileStartScore()
         }
 
         // First we get start locations for the major civs, on the second pass the city states (without predetermined starts) can squeeze in wherever
         // I hear copying code is good
-        val cityStatesWithStartingLocations =
-            gameInfo.tileMap.values
-                .filter { it.improvement != null && it.improvement!!.startsWith("StartingLocation ") }
-                .map { it.improvement!!.replace("StartingLocation ", "") }
-        val bestCivs = gameInfo.civilizations.filter { !it.isBarbarian() && (!it.isCityState() || it.civName in cityStatesWithStartingLocations) }
-        val bestLocations = getStartingLocations(bestCivs, gameInfo.tileMap, startScores)
-        for (civ in bestCivs)
-        {
-            if (civ.isCityState())  // Already have explicit starting locations
+        val civNamesWithStartingLocations = tileMap.startingLocationsByNation.keys
+        val bestCivs = gameInfo.civilizations.filter { !it.isBarbarian() && (!it.isCityState() || it.civName in civNamesWithStartingLocations) }
+        val bestLocations = getStartingLocations(bestCivs, tileMap, startScores)
+        for ((civ, tile) in bestLocations) {
+            if (civ.civName in civNamesWithStartingLocations)  // Already have explicit starting locations
                 continue
 
             // Mark the best start locations so we remember them for the second pass
-            bestLocations[civ]!!.improvement = "StartingLocation " + civ.civName
+            tileMap.addStartingLocation(civ.civName, tile)
         }
 
         val startingLocations = getStartingLocations(
                 gameInfo.civilizations.filter { !it.isBarbarian() },
-                gameInfo.tileMap, startScores)
+                tileMap, startScores)
 
         val settlerLikeUnits = ruleSet.units.filter {
-            it.value.uniqueObjects.any { it.placeholderText == Constants.settlerUnique }
+            it.value.uniqueObjects.any { unique -> unique.placeholderText == Constants.settlerUnique }
         }
 
         // no starting units for Barbarians and Spectators
@@ -241,8 +257,7 @@ object GameStarter {
                 addCityStateLuxury(gameInfo, startingLocation)
 
             for (tile in startingLocation.getTilesInDistance(3)) {
-                if (tile.improvement != null 
-                    && !tile.improvement!!.startsWith("StartingLocation") 
+                if (tile.improvement != null
                     && tile.getTileImprovement()!!.isAncientRuinsEquivalent()
                 ) {
                     tile.improvement = null // Remove ancient ruins in immediate vicinity
@@ -305,7 +320,7 @@ object GameStarter {
                 }
                 if (unit == "Worker" && "Worker" !in ruleSet.units) {
                     val buildableWorkerLikeUnits = ruleSet.units.filter {
-                        it.value.uniqueObjects.any { it.placeholderText == Constants.canBuildImprovements }
+                        it.value.uniqueObjects.any { unique -> unique.placeholderText == Constants.canBuildImprovements }
                                 && it.value.isBuildable(civ)
                                 && it.value.isCivilian()
                     }
@@ -353,18 +368,14 @@ object GameStarter {
                 landTilesInBigEnoughGroup.addAll(tilesInGroup)
         }
 
-        val tilesWithStartingLocations = tileMap.values
-                .filter { it.improvement != null && it.improvement!!.startsWith("StartingLocation ") }
-
-
         val civsOrderedByAvailableLocations = civs.shuffled()   // Order should be random since it determines who gets best start
             .sortedBy { civ ->
             when {
-                tilesWithStartingLocations.any { it.improvement == "StartingLocation " + civ.civName } -> 1 // harshest requirements
+                civ.civName in tileMap.startingLocationsByNation -> 1 // harshest requirements
                 civ.nation.startBias.contains("Tundra") -> 2    // Tundra starts are hard to find, so let's do them first
                 civ.nation.startBias.isNotEmpty() -> 3 // less harsh
-                else -> 4
-            }  // no requirements
+                else -> 4  // no requirements
+            }
         }
 
         for (minimumDistanceBetweenStartingLocations in tileMap.tileMatrix.size / 4 downTo 0) {
@@ -375,7 +386,7 @@ object GameStarter {
             val startingLocations = HashMap<CivilizationInfo, TileInfo>()
             for (civ in civsOrderedByAvailableLocations) {
                 var startingLocation: TileInfo
-                val presetStartingLocation = tilesWithStartingLocations.firstOrNull { it.improvement == "StartingLocation " + civ.civName }
+                val presetStartingLocation = tileMap.startingLocationsByNation[civ.civName]?.randomOrNull()  // in case map editor is extended to allow alternate starting locations for a nation
                 var distanceToNext = minimumDistanceBetweenStartingLocations
 
                 if (presetStartingLocation != null) startingLocation = presetStartingLocation
@@ -389,11 +400,14 @@ object GameStarter {
                     var preferredTiles = freeTiles.toList()
 
                     for (startBias in civ.nation.startBias) {
-                        if (startBias.startsWith("Avoid ")) {
-                            val tileToAvoid = startBias.removePrefix("Avoid [").removeSuffix("]")
-                            preferredTiles = preferredTiles.filter { !it.matchesTerrainFilter(tileToAvoid) }
-                        } else if (startBias == Constants.coast) preferredTiles = preferredTiles.filter { it.isCoastalTile() }
-                        else preferredTiles = preferredTiles.filter { it.matchesTerrainFilter(startBias) }
+                        preferredTiles = when {
+                            startBias.startsWith("Avoid [") -> {
+                                val tileToAvoid = startBias.removePrefix("Avoid [").removeSuffix("]")
+                                preferredTiles.filter { !it.matchesTerrainFilter(tileToAvoid) }
+                            }
+                            startBias == Constants.coast -> preferredTiles.filter { it.isCoastalTile() }
+                            else -> preferredTiles.filter { it.matchesTerrainFilter(startBias) }
+                        }
                     }
 
                     startingLocation = if (preferredTiles.isNotEmpty()) preferredTiles.last() else freeTiles.last()
diff --git a/core/src/com/unciv/logic/MapSaver.kt b/core/src/com/unciv/logic/MapSaver.kt
index 81c951189a..11f02f0de1 100644
--- a/core/src/com/unciv/logic/MapSaver.kt
+++ b/core/src/com/unciv/logic/MapSaver.kt
@@ -10,20 +10,32 @@ object MapSaver {
     fun json() = GameSaver.json()
 
     private const val mapsFolder = "maps"
+    private const val saveZipped = false
 
     private fun getMap(mapName:String) = Gdx.files.local("$mapsFolder/$mapName")
 
+    fun mapFromSavedString(mapString: String): TileMap {
+        val unzippedJson = try {
+            Gzip.unzip(mapString)
+        } catch (ex: Exception) {
+            mapString
+        }
+        return mapFromJson(unzippedJson)
+    }
+    fun mapToSavedString(tileMap: TileMap): String {
+        val mapJson = json().toJson(tileMap)
+        return if (saveZipped) Gzip.zip(mapJson) else mapJson
+    }
+
     fun saveMap(mapName: String,tileMap: TileMap) {
-        getMap(mapName).writeString(Gzip.zip(json().toJson(tileMap)), false)
+        getMap(mapName).writeString(mapToSavedString(tileMap), false)
     }
 
     fun loadMap(mapFile:FileHandle):TileMap {
-        val gzippedString = mapFile.readString()
-        val unzippedJson = Gzip.unzip(gzippedString)
-        return json().fromJson(TileMap::class.java, unzippedJson)
+        return mapFromSavedString(mapFile.readString())
     }
 
-    fun getMaps() = Gdx.files.local(mapsFolder).list()
+    fun getMaps(): Array<FileHandle> = Gdx.files.local(mapsFolder).list()
 
-    fun mapFromJson(json:String): TileMap = json().fromJson(TileMap::class.java, json)
+    private fun mapFromJson(json:String): TileMap = json().fromJson(TileMap::class.java, json)
 }
\ No newline at end of file
diff --git a/core/src/com/unciv/logic/map/MapParameters.kt b/core/src/com/unciv/logic/map/MapParameters.kt
index 2532f33943..8035d6e3e4 100644
--- a/core/src/com/unciv/logic/map/MapParameters.kt
+++ b/core/src/com/unciv/logic/map/MapParameters.kt
@@ -158,5 +158,6 @@ class MapParameters {
     }
 
     // For debugging and MapGenerator console output
-    override fun toString() = "($mapSize ${if (worldWrap)"wrapped " else ""}$shape $type, Seed $seed, $elevationExponent/$temperatureExtremeness/$resourceRichness/$vegetationRichness/$rareFeaturesRichness/$maxCoastExtension/$tilesPerBiomeArea/$waterThreshold)"
+    override fun toString() = if (name.isNotEmpty()) "\"$name\""
+        else "($mapSize ${if (worldWrap)"wrapped " else ""}$shape $type, Seed $seed, $elevationExponent/$temperatureExtremeness/$resourceRichness/$vegetationRichness/$rareFeaturesRichness/$maxCoastExtension/$tilesPerBiomeArea/$waterThreshold)"
 }
diff --git a/core/src/com/unciv/logic/map/MapUnit.kt b/core/src/com/unciv/logic/map/MapUnit.kt
index b5e29f5652..1e4f670b4f 100644
--- a/core/src/com/unciv/logic/map/MapUnit.kt
+++ b/core/src/com/unciv/logic/map/MapUnit.kt
@@ -733,7 +733,6 @@ class MapUnit {
 
         if (civInfo.isMajorCiv() 
             && tile.improvement != null
-            && !tile.improvement!!.startsWith("StartingLocation ")
             && tile.getTileImprovement()!!.isAncientRuinsEquivalent()
         )
             getAncientRuinBonus(tile)
diff --git a/core/src/com/unciv/logic/map/TileInfo.kt b/core/src/com/unciv/logic/map/TileInfo.kt
index 0f0c50f495..cb3eae889a 100644
--- a/core/src/com/unciv/logic/map/TileInfo.kt
+++ b/core/src/com/unciv/logic/map/TileInfo.kt
@@ -659,8 +659,7 @@ open class TileInfo {
             out.add("Terrain feature [$terrainFeature] does not exist in ruleset!")
         if (resource != null && !ruleset.tileResources.containsKey(resource))
             out.add("Resource [$resource] does not exist in ruleset!")
-        if (improvement != null && !improvement!!.startsWith("StartingLocation")
-                && !ruleset.tileImprovements.containsKey(improvement))
+        if (improvement != null && !ruleset.tileImprovements.containsKey(improvement))
             out.add("Improvement [$improvement] does not exist in ruleset!")
         return out
     }
@@ -756,9 +755,9 @@ open class TileInfo {
             roadStatus = RoadStatus.None
     }
 
-
     private fun normalizeTileImprovement(ruleset: Ruleset) {
-        if (improvement!!.startsWith("StartingLocation")) {
+        // This runs from map editor too, so the Pseudo-improvements for starting locations need to stay.
+        if (improvement!!.startsWith(TileMap.startingLocationPrefix)) {
             if (!isLand || getLastTerrain().impassable) improvement = null
             return
         }
diff --git a/core/src/com/unciv/logic/map/TileMap.kt b/core/src/com/unciv/logic/map/TileMap.kt
index b4a9eff6dd..e6b39fc0d8 100644
--- a/core/src/com/unciv/logic/map/TileMap.kt
+++ b/core/src/com/unciv/logic/map/TileMap.kt
@@ -10,11 +10,47 @@ import com.unciv.models.ruleset.Nation
 import com.unciv.models.ruleset.Ruleset
 import kotlin.math.abs
 
+/** An Unciv map with all properties as produced by the [map editor][com.unciv.ui.mapeditor.MapEditorScreen]
+ * or [MapGenerator][com.unciv.logic.map.mapgenerator.MapGenerator]; or as part of a running [game][GameInfo]. 
+ * 
+ * Note: Will be Serialized -> Take special care with lateinit and lazy! 
+ */
 class TileMap {
+    companion object {
+        const val startingLocationPrefix = "StartingLocation "
 
+        /**
+         * To be backwards compatible, a json without a startingLocations element will be recognized by an entry with this marker
+         * New saved maps will never have this marker and will always have a serialized startingLocations list even if empty.
+         * New saved maps will also never have "StartingLocation" improvements, these _must_ be converted before use anywhere outside map editor.
+         */
+        private const val legacyMarker = " Legacy "
+    }
+
+    //region Fields, Serialized
+
+    var mapParameters = MapParameters()
+
+    private var tileList = ArrayList<TileInfo>()
+
+    /** Structure geared for simple serialization by Gdx.Json (which is a little blind to kotlin collections, especially HashSet)
+     * @param position [Vector2] of the location
+     * @param nation Name of the nation
+     */
+    private data class StartingLocation(val position: Vector2 = Vector2.Zero, val nation: String = "")
+    private val startingLocations = arrayListOf(StartingLocation(Vector2.Zero, legacyMarker))
+
+    //endregion
+    //region Fields, Transient 
+
+    /** Attention: lateinit will _stay uninitialized_ while in MapEditorScreen! */
     @Transient
     lateinit var gameInfo: GameInfo
 
+    /** Keep a copy of the [Ruleset] object passer to setTransients, for now only to allow subsequent setTransients without. Copied on [clone]. */
+    @Transient
+    var ruleset: Ruleset? = null
+
     @Transient
     var tileMatrix = ArrayList<ArrayList<TileInfo?>>() // this works several times faster than a hashmap, the performance difference is really astounding
 
@@ -33,25 +69,31 @@ class TileMap {
     @delegate:Transient
     val naturalWonders: List<String> by lazy { tileList.asSequence().filter { it.isNaturalWonder() }.map { it.naturalWonder!! }.distinct().toList() }
 
-    var mapParameters = MapParameters()
-
-    private var tileList = ArrayList<TileInfo>()
-
+    // Excluded from Serialization by having no own backing field
     val values: Collection<TileInfo>
         get() = tileList
 
+    @Transient
+    val startingLocationsByNation = HashMap<String,HashSet<TileInfo>>()
+
+    //endregion
+    //region Constructors
+
     /** for json parsing, we need to have a default constructor */
     constructor()
 
-    /** generates an hexagonal map of given radius */
+    /** creates a hexagonal map of given radius (filled with grassland) */
     constructor(radius: Int, ruleset: Ruleset, worldWrap: Boolean = false) {
+        startingLocations.clear()
         for (vector in HexMath.getVectorsInDistance(Vector2.Zero, radius, worldWrap))
             tileList.add(TileInfo().apply { position = vector; baseTerrain = Constants.grassland })
         setTransients(ruleset)
     }
 
-    /** generates a rectangular map of given width and height*/
+    /** creates a rectangular map of given width and height (filled with grassland) */
     constructor(width: Int, height: Int, ruleset: Ruleset, worldWrap: Boolean = false) {
+        startingLocations.clear()
+
         // world-wrap maps must always have an even width, so round down
         val wrapAdjustedWidth = if (worldWrap && width % 2 != 0 ) width -1 else width
 
@@ -67,39 +109,57 @@ class TileMap {
         setTransients(ruleset)
     }
 
+    //endregion
+    //region Operators and Standards
+
+    /** @return a deep-copy clone of the serializable fields, no transients initialized */
     fun clone(): TileMap {
         val toReturn = TileMap()
         toReturn.tileList.addAll(tileList.map { it.clone() })
         toReturn.mapParameters = mapParameters
+        toReturn.ruleset = ruleset
+        toReturn.startingLocations.clear()
+        toReturn.startingLocations.ensureCapacity(startingLocations.size)
+        toReturn.startingLocations.addAll(startingLocations)
         return toReturn
     }
 
-    operator fun contains(vector: Vector2) = contains(vector.x.toInt(), vector.y.toInt())
+    operator fun contains(vector: Vector2) =
+        contains(vector.x.toInt(), vector.y.toInt())
 
-    fun contains(x: Int, y: Int): Boolean {
+    operator fun get(vector: Vector2) =
+        get(vector.x.toInt(), vector.y.toInt())
+
+    fun contains(x: Int, y: Int) =
+        getOrNull(x, y) != null
+
+    operator fun get(x: Int, y: Int) =
+        tileMatrix[x - leftX][y - bottomY]!!
+
+    /** @return tile at hex coordinates ([x],[y]) or null if they are outside the map. Does *not* respect world wrap, use [getIfTileExistsOrNull] for that. */
+    private fun getOrNull (x: Int, y: Int): TileInfo? {
         val arrayXIndex = x - leftX
-        if (arrayXIndex < 0 || arrayXIndex >= tileMatrix.size) return false
+        if (arrayXIndex < 0 || arrayXIndex >= tileMatrix.size) return null
         val arrayYIndex = y - bottomY
-        if (arrayYIndex < 0 || arrayYIndex >= tileMatrix[arrayXIndex].size) return false
-        return tileMatrix[arrayXIndex][arrayYIndex] != null
+        if (arrayYIndex < 0 || arrayYIndex >= tileMatrix[arrayXIndex].size) return null
+        return tileMatrix[arrayXIndex][arrayYIndex]
     }
 
-    operator fun get(x: Int, y: Int): TileInfo {
-        val arrayXIndex = x - leftX
-        val arrayYIndex = y - bottomY
-        return tileMatrix[arrayXIndex][arrayYIndex]!!
-    }
-
-    operator fun get(vector: Vector2): TileInfo {
-        return get(vector.x.toInt(), vector.y.toInt())
-    }
+    //endregion
+    //region Pure Functions
 
+    /** @return All tiles in a hexagon of radius [distance], including the tile at [origin] and all up to [distance] steps away.
+     *  Respects map edges and world wrap. */
     fun getTilesInDistance(origin: Vector2, distance: Int): Sequence<TileInfo> =
             getTilesInDistanceRange(origin, 0..distance)
-
+    
+    /** @return All tiles in a hexagonal ring around [origin] with the distances in [range]. Excludes the [origin] tile unless [range] starts at 0.
+     *  Respects map edges and world wrap. */
     fun getTilesInDistanceRange(origin: Vector2, range: IntRange): Sequence<TileInfo> =
             range.asSequence().flatMap { getTilesAtDistance(origin, it) }
 
+    /** @return All tiles in a hexagonal ring 1 tile wide around [origin] with the [distance]. Contains the [origin] if and only if [distance] is <= 0.
+     *  Respects map edges and world wrap. */
     fun getTilesAtDistance(origin: Vector2, distance: Int): Sequence<TileInfo> =
             if (distance <= 0) // silently take negatives.
                 sequenceOf(get(origin))
@@ -133,6 +193,7 @@ class TileMap {
                     }
                 }.filterNotNull()
 
+    /** @return tile at hex coordinates ([x],[y]) or null if they are outside the map. Respects map edges and world wrap. */
     private fun getIfTileExistsOrNull(x: Int, y: Int): TileInfo? {
         if (contains(x, y))
             return get(x, y)
@@ -156,6 +217,166 @@ class TileMap {
         return null
     }
 
+    /**
+     * Returns the clockPosition of [otherTile] seen from [tile]'s position
+     * Returns -1 if not neighbors
+     */
+    fun getNeighborTileClockPosition(tile: TileInfo, otherTile: TileInfo): Int {
+        val radius = if (mapParameters.shape == MapShape.rectangular)
+            mapParameters.mapSize.width / 2
+        else mapParameters.mapSize.radius
+
+        val xDifference = tile.position.x - otherTile.position.x
+        val yDifference = tile.position.y - otherTile.position.y
+        val xWrapDifferenceBottom = tile.position.x - (otherTile.position.x - radius)
+        val yWrapDifferenceBottom = tile.position.y - (otherTile.position.y - radius)
+        val xWrapDifferenceTop = tile.position.x - (otherTile.position.x + radius)
+        val yWrapDifferenceTop = tile.position.y - (otherTile.position.y + radius)
+
+        return when {
+            xDifference == 1f && yDifference == 1f -> 6 // otherTile is below
+            xDifference == -1f && yDifference == -1f -> 12 // otherTile is above
+            xDifference == 1f || xWrapDifferenceBottom == 1f -> 4 // otherTile is bottom-right
+            yDifference == 1f || yWrapDifferenceBottom == 1f -> 8 // otherTile is bottom-left
+            xDifference == -1f || xWrapDifferenceTop == -1f -> 10 // otherTile is top-left
+            yDifference == -1f || yWrapDifferenceTop == -1f -> 2 // otherTile is top-right
+            else -> -1
+        }
+    }
+
+    /** Convert relative direction of [otherTile] seen from [tile]'s position into a vector
+     * in world coordinates of length sqrt(3), so that it can be used to go from tile center to
+     * the edge of the hex in that direction (meaning the center of the border between the hexes)
+     */
+    fun getNeighborTilePositionAsWorldCoords(tile: TileInfo, otherTile: TileInfo): Vector2 =
+        HexMath.getClockDirectionToWorldVector(getNeighborTileClockPosition(tile, otherTile))
+
+    /**
+     * Returns the closest position to (0, 0) outside the map which can be wrapped
+     * to the position of the given vector
+     */
+    fun getUnWrappedPosition(position: Vector2): Vector2 {
+        if (!contains(position))
+            return position //The position is outside the map so its unwrapped already
+
+        val radius = if (mapParameters.shape == MapShape.rectangular)
+            mapParameters.mapSize.width / 2
+        else mapParameters.mapSize.radius
+
+        val vectorUnwrappedLeft = Vector2(position.x + radius, position.y - radius)
+        val vectorUnwrappedRight = Vector2(position.x - radius, position.y + radius)
+
+        return if (vectorUnwrappedRight.len() < vectorUnwrappedLeft.len())
+            vectorUnwrappedRight
+        else
+            vectorUnwrappedLeft
+    }
+
+    /** @return List of tiles visible from location [position] for a unit with sight range [sightDistance] */
+    fun getViewableTiles(position: Vector2, sightDistance: Int): List<TileInfo> {
+        val viewableTiles = getTilesInDistance(position, 1).toMutableList()
+        val currentTileHeight = get(position).getHeight()
+
+        for (i in 1..sightDistance) { // in each layer,
+            // This is so we don't use tiles in the same distance to "see over",
+            // that is to say, the "viewableTiles.contains(it) check will return false for neighbors from the same distance
+            val tilesToAddInDistanceI = ArrayList<TileInfo>()
+
+            for (cTile in getTilesAtDistance(position, i)) { // for each tile in that layer,
+                val cTileHeight = cTile.getHeight()
+
+                /*
+            Okay so, if we're looking at a tile from a to c with b in the middle,
+            we have several scenarios:
+            1. a>b -  - I can see everything, b does not hide c
+            2. a==b
+                2.1 c>b - c is tall enough I can see it over b!
+                2.2 b blocks view from same-elevation tiles - hides c
+                2.3 none of the above - I can see c
+            3. a<b
+                3.1 b>=c - b hides c
+                3.2 b<c - c is tall enough I can see it over b!
+
+            This can all be summed up as "I can see c if a>b || c>b || (a==b && b !blocks same-elevation view)"
+            */
+
+                val containsViewableNeighborThatCanSeeOver = cTile.neighbors.any {
+                        bNeighbor: TileInfo ->
+                    val bNeighborHeight = bNeighbor.getHeight()
+                    viewableTiles.contains(bNeighbor) && (
+                            currentTileHeight > bNeighborHeight // a>b
+                                    || cTileHeight > bNeighborHeight // c>b
+                                    || currentTileHeight == bNeighborHeight // a==b
+                                    && !bNeighbor.hasUnique("Blocks line-of-sight from tiles at same elevation"))
+                }
+                if (containsViewableNeighborThatCanSeeOver) tilesToAddInDistanceI.add(cTile)
+            }
+            viewableTiles.addAll(tilesToAddInDistanceI)
+        }
+
+        return viewableTiles
+    }
+
+    /** Strips all units from [TileMap]
+     * @return stripped [clone] of [TileMap]
+     */
+    fun stripAllUnits(): TileMap {
+        return clone().apply { tileList.forEach { it.stripUnits() } }
+    }
+
+    /** Build a list of incompatibilities of a map with a ruleset for the new game loader
+     * 
+     *  Is run before setTransients, so make do without startingLocationsByNation
+     */
+    fun getRulesetIncompatibility(ruleset: Ruleset): HashSet<String> {
+        val rulesetIncompatibilities = HashSet<String>()
+        for (set in values.map { it.getRulesetIncompatibility(ruleset) })
+            rulesetIncompatibilities.addAll(set)
+        for ((_, nationName) in startingLocations) {
+            if (nationName !in ruleset.nations)
+                rulesetIncompatibilities.add("Nation [$nationName] does not exist in ruleset!")
+        }
+        rulesetIncompatibilities.remove("")
+        return rulesetIncompatibilities
+    }
+
+    //endregion
+    //region State-Changing Methods
+
+    /** Initialize transients - without, most operations, like [get] from coordinates, will fail.
+     * @param ruleset Required unless this is a clone of an initialized TileMap including one
+     * @param setUnitCivTransients when false Civ-specific parts of unit initialization are skipped, for the map editor.
+     */
+    fun setTransients(ruleset: Ruleset? = null, setUnitCivTransients: Boolean = true) {
+        if (ruleset != null) this.ruleset = ruleset
+        if (this.ruleset == null) throw(IllegalStateException("TileMap.setTransients called without ruleset"))
+
+        if (tileMatrix.isEmpty()) {
+            val topY = tileList.asSequence().map { it.position.y.toInt() }.maxOrNull()!!
+            bottomY = tileList.asSequence().map { it.position.y.toInt() }.minOrNull()!!
+            val rightX = tileList.asSequence().map { it.position.x.toInt() }.maxOrNull()!!
+            leftX = tileList.asSequence().map { it.position.x.toInt() }.minOrNull()!!
+
+            for (x in leftX..rightX) {
+                val row = ArrayList<TileInfo?>()
+                for (y in bottomY..topY) row.add(null)
+                tileMatrix.add(row)
+            }
+        } else {
+            // Yes the map generator calls this repeatedly, and we don't want to end up with an oversized tileMatrix
+            // rightX is -leftX or -leftX + 1
+            if (tileMatrix.size != 1 - 2 * leftX && tileMatrix.size != 2 - 2 * leftX)
+                throw(IllegalStateException("TileMap.setTransients called on existing tileMatrix of different size"))
+        }
+
+        for (tileInfo in values) {
+            tileMatrix[tileInfo.position.x.toInt() - leftX][tileInfo.position.y.toInt() - bottomY] = tileInfo
+            tileInfo.tileMap = this
+            tileInfo.ruleset = this.ruleset!!
+            tileInfo.setTerrainTransients()
+            tileInfo.setUnitTransients(setUnitCivTransients)
+        }
+    }
 
     /** Tries to place the [unitName] into the [TileInfo] closest to the given [position]
      * @param position where to try to place the unit (or close - max 10 tiles distance)
@@ -224,64 +445,13 @@ class TileMap {
     }
 
 
-    fun getViewableTiles(position: Vector2, sightDistance: Int): List<TileInfo> {
-        val viewableTiles = getTilesInDistance(position, 1).toMutableList()
-        val currentTileHeight = get(position).getHeight()
-
-        for (i in 1..sightDistance) { // in each layer,
-            // This is so we don't use tiles in the same distance to "see over",
-            // that is to say, the "viewableTiles.contains(it) check will return false for neighbors from the same distance
-            val tilesToAddInDistanceI = ArrayList<TileInfo>()
-
-            for (cTile in getTilesAtDistance(position, i)) { // for each tile in that layer,
-                val cTileHeight = cTile.getHeight()
-
-                /*
-            Okay so, if we're looking at a tile from a to c with b in the middle,
-            we have several scenarios:
-            1. a>b -  - I can see everything, b does not hide c
-            2. a==b
-                2.1 c>b - c is tall enough I can see it over b!
-                2.2 b blocks view from same-elevation tiles - hides c
-                2.3 none of the above - I can see c
-            3. a<b
-                3.1 b>=c - b hides c
-                3.2 b<c - c is tall enough I can see it over b!
-
-            This can all be summed up as "I can see c if a>b || c>b || (a==b && b !blocks same-elevation view)"
-            */
-
-                val containsViewableNeighborThatCanSeeOver = cTile.neighbors.any {
-                        bNeighbor: TileInfo ->
-                    val bNeighborHeight = bNeighbor.getHeight()
-                    viewableTiles.contains(bNeighbor) && (
-                            currentTileHeight > bNeighborHeight // a>b
-                                    || cTileHeight > bNeighborHeight // c>b
-                                    || currentTileHeight == bNeighborHeight // a==b
-                                        && !bNeighbor.hasUnique("Blocks line-of-sight from tiles at same elevation"))
-                }
-                if (containsViewableNeighborThatCanSeeOver) tilesToAddInDistanceI.add(cTile)
-            }
-            viewableTiles.addAll(tilesToAddInDistanceI)
-        }
-
-        return viewableTiles
-    }
-
-    /** Strips all units from [TileMap]
-     * @return stripped clone of [TileMap]
-     */
-    fun stripAllUnits(): TileMap {
-        return clone().apply { tileList.forEach { it.stripUnits() } }
-    }
-
-    /** Strips all units and starting location from [TileMap] for specified [Player]
+    /** Strips all units and starting locations from [TileMap] for specified [Player]
      * Operation in place
-     * @param player units of player to be stripped off
+     * @param player units of this player will be removed
      */
     fun stripPlayer(player: Player) {
         tileList.forEach {
-            if (it.improvement == "StartingLocation " + player.chosenCiv) {
+            if (it.improvement == startingLocationPrefix + player.chosenCiv) {
                 it.improvement = null
             }
             for (unit in it.getUnits()) if (unit.owner == player.chosenCiv) unit.removeFromTile()
@@ -295,8 +465,8 @@ class TileMap {
      */
     fun switchPlayersNation(player: Player, newNation: Nation) {
         tileList.forEach {
-            if (it.improvement == "StartingLocation " + player.chosenCiv) {
-                it.improvement = "StartingLocation " + newNation.name
+            if (it.improvement == startingLocationPrefix + player.chosenCiv) {
+                it.improvement = startingLocationPrefix + newNation.name
             }
             for (unit in it.getUnits()) if (unit.owner == player.chosenCiv) {
                 unit.owner = newNation.name
@@ -305,80 +475,61 @@ class TileMap {
         }
     }
 
-    fun setTransients(ruleset: Ruleset, setUnitCivTransients: Boolean = true) { // In the map editor, no Civs or Game exist, so we won't set the unit transients
-        val topY = tileList.asSequence().map { it.position.y.toInt() }.maxOrNull()!!
-        bottomY = tileList.asSequence().map { it.position.y.toInt() }.minOrNull()!!
-        val rightX = tileList.asSequence().map { it.position.x.toInt() }.maxOrNull()!!
-        leftX = tileList.asSequence().map { it.position.x.toInt() }.minOrNull()!!
-
-        for (x in leftX..rightX) {
-            val row = ArrayList<TileInfo?>()
-            for (y in bottomY..topY) row.add(null)
-            tileMatrix.add(row)
-        }
-
-        for (tileInfo in values) {
-            tileMatrix[tileInfo.position.x.toInt() - leftX][tileInfo.position.y.toInt() - bottomY] = tileInfo
-            tileInfo.tileMap = this
-            tileInfo.ruleset = ruleset
-            tileInfo.setTerrainTransients()
-            tileInfo.setUnitTransients(setUnitCivTransients)
+    /**
+     *  Initialize startingLocations transients, including legacy support (maps saved with placeholder improvements)
+     */
+    fun setStartingLocationsTransients() {
+        if (startingLocations.size == 1 && startingLocations[0].nation == legacyMarker)
+            return translateStartingLocationsFromMap()
+        startingLocationsByNation.clear()
+        for ((position, nationName) in startingLocations) {
+            val nationSet = startingLocationsByNation[nationName] ?: hashSetOf<TileInfo>().also { startingLocationsByNation[nationName] = it }
+            nationSet.add(get(position))
         }
     }
 
     /**
-     * Returns the clockPosition of otherTile seen from tile's position
-     * Returns -1 if not neighbors
+     *  Scan and remove placeholder improvements from map and build startingLocations from them
      */
-    fun getNeighborTileClockPosition(tile: TileInfo, otherTile: TileInfo): Int {
-        val radius = if (mapParameters.shape == MapShape.rectangular)
-                mapParameters.mapSize.width / 2
-            else mapParameters.mapSize.radius
+    fun translateStartingLocationsFromMap() {
+        startingLocations.clear()
+        tileList.asSequence()
+            .filter { it.improvement?.startsWith(startingLocationPrefix) == true }
+            .map { it to StartingLocation(it.position, it.improvement!!.removePrefix(startingLocationPrefix)) }
+            .sortedBy { it.second.nation }  // vanity, or to make diffs between un-gzipped map files easier
+            .forEach { (tile, startingLocation) ->
+                tile.improvement = null
+                startingLocations.add(startingLocation)
+            }
+        setStartingLocationsTransients()
+    }
 
-        val xDifference = tile.position.x - otherTile.position.x
-        val yDifference = tile.position.y - otherTile.position.y
-        val xWrapDifferenceBottom = tile.position.x - (otherTile.position.x - radius)
-        val yWrapDifferenceBottom = tile.position.y - (otherTile.position.y - radius)
-        val xWrapDifferenceTop = tile.position.x - (otherTile.position.x + radius)
-        val yWrapDifferenceTop = tile.position.y - (otherTile.position.y + radius)
-
-        return when {
-            xDifference == 1f && yDifference == 1f -> 6 // otherTile is below
-            xDifference == -1f && yDifference == -1f -> 12 // otherTile is above
-            xDifference == 1f || xWrapDifferenceBottom == 1f -> 4 // otherTile is bottom-right
-            yDifference == 1f || yWrapDifferenceBottom == 1f -> 8 // otherTile is bottom-left
-            xDifference == -1f || xWrapDifferenceTop == -1f -> 10 // otherTile is top-left
-            yDifference == -1f || yWrapDifferenceTop == -1f -> 2 // otherTile is top-right
-            else -> -1
+    /**
+     *  Place placeholder improvements on the map for the startingLocations entries.
+     *  
+     *  **For use by the map editor only**
+     *  
+     *  This is a copy, the startingLocations array and transients are untouched.
+     *  Any actual improvements on the tiles will be overwritten.
+     */
+    fun translateStartingLocationsToMap() {
+        for ((position, nationName) in startingLocations) {
+            get(position).improvement = startingLocationPrefix + nationName
         }
     }
 
-    /** Convert relative direction of otherTile seen from tile's position into a vector
-     * in world coordinates of length sqrt(3), so that it can be used to go from tile center to
-     * the edge of the hex in that direction (meaning the center of the border between the hexes)
-     */
-    fun getNeighborTilePositionAsWorldCoords(tile: TileInfo, otherTile: TileInfo): Vector2 =
-        HexMath.getClockDirectionToWorldVector(getNeighborTileClockPosition(tile, otherTile))
-
-
-    /**
-     * Returns the closest position to (0, 0) outside the map which can be wrapped
-     * to the position of the given vector
-     */
-    fun getUnWrappedPosition(position: Vector2): Vector2 {
-        if (!contains(position))
-            return position //The position is outside the map so its unwrapped already
-
-        var radius = mapParameters.mapSize.radius
-        if (mapParameters.shape == MapShape.rectangular)
-            radius = mapParameters.mapSize.width / 2
-
-        val vectorUnwrappedLeft = Vector2(position.x + radius, position.y - radius)
-        val vectorUnwrappedRight = Vector2(position.x - radius, position.y + radius)
-
-        return if (vectorUnwrappedRight.len() < vectorUnwrappedLeft.len())
-            vectorUnwrappedRight
-        else
-            vectorUnwrappedLeft
+    /** Adds a starting position, maintaining the transients */
+    fun addStartingLocation(nationName: String, tile: TileInfo) {
+        startingLocations.add(StartingLocation(tile.position, nationName))
+        val nationSet = startingLocationsByNation[nationName] ?: hashSetOf<TileInfo>().also { startingLocationsByNation[nationName] = it }
+        nationSet.add(tile)
     }
+
+    /** Clears starting positions, e.g. after GameStarter is done with them. Does not clear the pseudo-improvements. */
+    fun clearStartingLocations() {
+        startingLocations.clear()
+        startingLocationsByNation.clear()
+    }
+
+    //endregion
 }
diff --git a/core/src/com/unciv/models/metadata/GameParameters.kt b/core/src/com/unciv/models/metadata/GameParameters.kt
index cc5aef0cae..a4752e16e9 100644
--- a/core/src/com/unciv/models/metadata/GameParameters.kt
+++ b/core/src/com/unciv/models/metadata/GameParameters.kt
@@ -40,6 +40,7 @@ class GameParameters { // Default values are the default new game
         parameters.noBarbarians = noBarbarians
         parameters.oneCityChallenge = oneCityChallenge
         parameters.nuclearWeaponsEnabled = nuclearWeaponsEnabled
+        parameters.religionEnabled = religionEnabled
         parameters.victoryTypes = ArrayList(victoryTypes)
         parameters.startingEra = startingEra
         parameters.isOnlineMultiplayer = isOnlineMultiplayer
@@ -47,4 +48,24 @@ class GameParameters { // Default values are the default new game
         parameters.mods = LinkedHashSet(mods)
         return parameters
     }
+
+    // For debugging and MapGenerator console output
+    override fun toString() = "($difficulty $gameSpeed $startingEra, " +
+            "${players.count { it.playerType == PlayerType.Human }} ${PlayerType.Human} " +
+            "${players.count { it.playerType == PlayerType.AI }} ${PlayerType.AI} " +
+            "$numberOfCityStates CS, " +
+            sequence<String> {
+                if (isOnlineMultiplayer) yield("Online Multiplayer")
+                if (noBarbarians) yield("No barbs")
+                if (oneCityChallenge) yield("OCC")
+                if (!nuclearWeaponsEnabled) yield("No nukes")
+                if (religionEnabled) yield("Religion")
+                if (godMode) yield("God mode")
+                if (VictoryType.Cultural !in victoryTypes) yield("No ${VictoryType.Cultural} Victory")
+                if (VictoryType.Diplomatic in victoryTypes) yield("${VictoryType.Diplomatic} Victory")
+                if (VictoryType.Domination !in victoryTypes) yield("No ${VictoryType.Domination} Victory")
+                if (VictoryType.Scientific !in victoryTypes) yield("No ${VictoryType.Scientific} Victory")
+            }.joinToString() +
+            (if (mods.isEmpty()) ", no mods" else mods.joinToString(",", ", mods=(", ")", 6) ) +
+            ")"
 }
\ No newline at end of file
diff --git a/core/src/com/unciv/ui/mapeditor/MapEditorOptionsTable.kt b/core/src/com/unciv/ui/mapeditor/MapEditorOptionsTable.kt
index ef991c4916..82bb319997 100644
--- a/core/src/com/unciv/ui/mapeditor/MapEditorOptionsTable.kt
+++ b/core/src/com/unciv/ui/mapeditor/MapEditorOptionsTable.kt
@@ -162,7 +162,7 @@ class MapEditorOptionsTable(val mapEditorScreen: MapEditorScreen): Table(CameraS
 
             val nationImage = getHex(ImageGetter.getNationIndicator(nation, 40f))
             nationImage.onClick {
-                val improvementName = "StartingLocation " + nation.name
+                val improvementName = TileMap.startingLocationPrefix + nation.name
                 tileAction = {
                     it.improvement = improvementName
                     for ((tileInfo, tileGroups) in mapEditorScreen.mapHolder.tileGroups) {
@@ -267,17 +267,6 @@ class MapEditorOptionsTable(val mapEditorScreen: MapEditorScreen): Table(CameraS
         editorPickTable.add(AutoScrollPane(unitsTable)).height(scrollPanelHeight)
     }
 
-    private fun nationsFromMap(tileMap: TileMap): ArrayList<Nation> {
-        val tilesWithStartingLocations = tileMap.values
-                .filter { it.improvement != null && it.improvement!!.startsWith("StartingLocation ") }
-        var nations = ArrayList<Nation>()
-        for (tile in tilesWithStartingLocations) {
-            var civName = tile.improvement!!.removePrefix("StartingLocation ")
-            nations.add(ruleset.nations[civName]!!)
-        }
-        return nations
-    }
-
     private fun getPlayerIndexString(player: Player): String {
         val index = gameParameters.players.indexOf(player) + 1
         return "Player [$index]".tr()
diff --git a/core/src/com/unciv/ui/mapeditor/MapEditorScreen.kt b/core/src/com/unciv/ui/mapeditor/MapEditorScreen.kt
index 65b0c6fb32..8a6f2c4ec8 100644
--- a/core/src/com/unciv/ui/mapeditor/MapEditorScreen.kt
+++ b/core/src/com/unciv/ui/mapeditor/MapEditorScreen.kt
@@ -35,6 +35,8 @@ class MapEditorScreen(): CameraStageBaseScreen() {
     private fun initialize() {
         ImageGetter.setNewRuleset(ruleset)
         tileMap.setTransients(ruleset,false)
+        tileMap.setStartingLocationsTransients()
+        tileMap.translateStartingLocationsToMap()
         UncivGame.Current.translations.translationActiveMods = ruleset.mods
 
         mapHolder = EditorMapHolder(this, tileMap)
diff --git a/core/src/com/unciv/ui/mapeditor/SaveAndLoadMapScreen.kt b/core/src/com/unciv/ui/mapeditor/SaveAndLoadMapScreen.kt
index e93ab867ca..123573085e 100644
--- a/core/src/com/unciv/ui/mapeditor/SaveAndLoadMapScreen.kt
+++ b/core/src/com/unciv/ui/mapeditor/SaveAndLoadMapScreen.kt
@@ -6,14 +6,12 @@ import com.badlogic.gdx.graphics.Color
 import com.badlogic.gdx.scenes.scene2d.ui.Table
 import com.badlogic.gdx.scenes.scene2d.ui.TextButton
 import com.badlogic.gdx.scenes.scene2d.ui.TextField
-import com.badlogic.gdx.utils.Json
 import com.unciv.logic.MapSaver
 import com.unciv.logic.map.MapType
 import com.unciv.logic.map.TileMap
 import com.unciv.models.ruleset.RulesetCache
 import com.unciv.models.translations.tr
 import com.unciv.ui.pickerscreens.PickerScreen
-import com.unciv.ui.saves.Gzip
 import com.unciv.ui.utils.*
 import kotlin.concurrent.thread
 import com.unciv.ui.utils.AutoScrollPane as ScrollPane
@@ -35,7 +33,7 @@ class SaveAndLoadMapScreen(mapToSave: TileMap?, save:Boolean = false, previousSc
                 mapToSave.mapParameters.type = MapType.custom
                 thread(name = "SaveMap") {
                     try {
-                        MapSaver.saveMap(mapNameTextField.text, mapToSave)
+                        MapSaver.saveMap(mapNameTextField.text, getMapCloneForSave(mapToSave))
                         Gdx.app.postRunnable {
                             Gdx.input.inputProcessor = null // This is to stop ANRs happening here, until the map editor screen sets up.
                             game.setScreen(MapEditorScreen(mapToSave))
@@ -119,9 +117,7 @@ class SaveAndLoadMapScreen(mapToSave: TileMap?, save:Boolean = false, previousSc
         if (save) {
             val copyMapAsTextButton = "Copy to clipboard".toTextButton()
             val copyMapAsTextAction = {
-                val json = Json().toJson(mapToSave)
-                val base64Gzip = Gzip.zip(json)
-                Gdx.app.clipboard.contents = base64Gzip
+                Gdx.app.clipboard.contents = MapSaver.mapToSavedString(getMapCloneForSave(mapToSave!!))
             }
             copyMapAsTextButton.onClick (copyMapAsTextAction)
             keyPressDispatcher[KeyCharAndCode.ctrl('C')] = copyMapAsTextAction
@@ -132,8 +128,7 @@ class SaveAndLoadMapScreen(mapToSave: TileMap?, save:Boolean = false, previousSc
             val loadFromClipboardAction = {
                 try {
                     val clipboardContentsString = Gdx.app.clipboard.contents.trim()
-                    val decoded = Gzip.unzip(clipboardContentsString)
-                    val loadedMap = MapSaver.mapFromJson(decoded)
+                    val loadedMap = MapSaver.mapFromSavedString(clipboardContentsString)
                     game.setScreen(MapEditorScreen(loadedMap))
                 } catch (ex: Exception) {
                     couldNotLoadMapLabel.isVisible = true
@@ -187,4 +182,8 @@ class SaveAndLoadMapScreen(mapToSave: TileMap?, save:Boolean = false, previousSc
         }
     }
 
+    fun getMapCloneForSave(mapToSave: TileMap) = mapToSave!!.clone().also {
+            it.setTransients(setUnitCivTransients = false)
+            it.translateStartingLocationsFromMap()
+        }
 }
diff --git a/core/src/com/unciv/ui/newgamescreen/NewGameScreen.kt b/core/src/com/unciv/ui/newgamescreen/NewGameScreen.kt
index 0cc835da92..a70962ec93 100644
--- a/core/src/com/unciv/ui/newgamescreen/NewGameScreen.kt
+++ b/core/src/com/unciv/ui/newgamescreen/NewGameScreen.kt
@@ -91,10 +91,7 @@ class NewGameScreen(
 
             if (mapOptionsTable.mapTypeSelectBox.selected.value == MapType.custom){
                 val map = MapSaver.loadMap(gameSetupInfo.mapFile!!)
-                val rulesetIncompatibilities = HashSet<String>()
-                for (set in map.values.map { it.getRulesetIncompatibility(ruleset) })
-                    rulesetIncompatibilities.addAll(set)
-                rulesetIncompatibilities.remove("")
+                val rulesetIncompatibilities = map.getRulesetIncompatibility(ruleset)
 
                 if (rulesetIncompatibilities.isNotEmpty()) {
                     val incompatibleMap = Popup(this)
diff --git a/core/src/com/unciv/ui/tilegroups/TileGroup.kt b/core/src/com/unciv/ui/tilegroups/TileGroup.kt
index 28b3ae035a..70d7e4b41b 100644
--- a/core/src/com/unciv/ui/tilegroups/TileGroup.kt
+++ b/core/src/com/unciv/ui/tilegroups/TileGroup.kt
@@ -11,6 +11,7 @@ import com.unciv.UncivGame
 import com.unciv.logic.civilization.CivilizationInfo
 import com.unciv.logic.map.RoadStatus
 import com.unciv.logic.map.TileInfo
+import com.unciv.logic.map.TileMap
 import com.unciv.ui.cityscreen.YieldGroup
 import com.unciv.ui.utils.ImageGetter
 import com.unciv.ui.utils.center
@@ -331,9 +332,11 @@ open class TileGroup(var tileInfo: TileInfo, var tileSetStrings:TileSetStrings,
     }
 
     private fun removeMissingModReferences() {
+        // This runs from map editor too, so the Pseudo-improvements for starting locations need to stay.
+        // The nations can be checked.
         val improvementName = tileInfo.improvement
-        if(improvementName != null && improvementName.startsWith("StartingLocation ")){
-            val nationName = improvementName.removePrefix("StartingLocation ")
+        if (improvementName != null && improvementName.startsWith(TileMap.startingLocationPrefix)) {
+            val nationName = improvementName.removePrefix(TileMap.startingLocationPrefix)
             if (!tileInfo.ruleset.nations.containsKey(nationName))
                 tileInfo.improvement = null
         }
diff --git a/core/src/com/unciv/ui/utils/ImageGetter.kt b/core/src/com/unciv/ui/utils/ImageGetter.kt
index bccbd21561..5a1149e214 100644
--- a/core/src/com/unciv/ui/utils/ImageGetter.kt
+++ b/core/src/com/unciv/ui/utils/ImageGetter.kt
@@ -16,6 +16,7 @@ import com.badlogic.gdx.scenes.scene2d.utils.TextureRegionDrawable
 import com.badlogic.gdx.utils.Align
 import com.unciv.Constants
 import com.unciv.UncivGame
+import com.unciv.logic.map.TileMap
 import com.unciv.models.ruleset.Era
 import com.unciv.models.ruleset.Nation
 import com.unciv.models.ruleset.Ruleset
@@ -253,8 +254,8 @@ object ImageGetter {
     fun getImprovementIcon(improvementName: String, size: Float = 20f): Actor {
         if (improvementName.startsWith("Remove") || improvementName == Constants.cancelImprovementOrder)
             return Table().apply { add(getImage("OtherIcons/Stop")).size(size) }
-        if (improvementName.startsWith("StartingLocation ")) {
-            val nationName = improvementName.removePrefix("StartingLocation ")
+        if (improvementName.startsWith(TileMap.startingLocationPrefix)) {
+            val nationName = improvementName.removePrefix(TileMap.startingLocationPrefix)
             val nation = ruleset.nations[nationName]!!
             return getNationIndicator(nation, size)
         }
diff --git a/core/src/com/unciv/ui/worldscreen/bottombar/TileInfoTable.kt b/core/src/com/unciv/ui/worldscreen/bottombar/TileInfoTable.kt
index c0ffab54f2..e5fc0e4c3a 100644
--- a/core/src/com/unciv/ui/worldscreen/bottombar/TileInfoTable.kt
+++ b/core/src/com/unciv/ui/worldscreen/bottombar/TileInfoTable.kt
@@ -24,9 +24,9 @@ class TileInfoTable(private val viewingCiv :CivilizationInfo) : Table(CameraStag
             add(getStatsTable(tile))
             add( MarkupRenderer.render(tile.toMarkup(viewingCiv), padding = 0f, noLinkImages = true) {
                 UncivGame.Current.setScreen(CivilopediaScreen(viewingCiv.gameInfo.ruleSet, link = it))
-            } ).pad(5f)
-            // For debug only!
-//            add(tile.position.toString().toLabel()).colspan(2).pad(10f)
+            } ).pad(5f).row()
+            if (UncivGame.Current.viewEntireMapForDebug)
+                add(tile.position.run { "(${x.toInt()},${y.toInt()})" }.toLabel()).colspan(2).pad(5f)
         }
 
         pack()