diff --git a/core/src/com/unciv/models/ruleset/tile/Terrain.kt b/core/src/com/unciv/models/ruleset/tile/Terrain.kt
index 8bcc92b4ac..ab43d6090e 100644
--- a/core/src/com/unciv/models/ruleset/tile/Terrain.kt
+++ b/core/src/com/unciv/models/ruleset/tile/Terrain.kt
@@ -144,8 +144,15 @@ class Terrain : RulesetStatsObject() {
         return textList
     }
 
+    /** Terrain filter matching is "pure" - input always returns same output, and it's called a bajillion times */
+    val cachedMatchesFilterResult = HashMap<String, Boolean>()
+
     fun matchesFilter(filter: String): Boolean {
-        return MultiFilter.multiFilter(filter, { matchesSingleFilter(it) })
+        val cachedAnswer = cachedMatchesFilterResult[filter]
+        if (cachedAnswer != null) return cachedAnswer
+        val newAnswer = MultiFilter.multiFilter(filter, { matchesSingleFilter(it) })
+        cachedMatchesFilterResult[filter] = newAnswer
+        return newAnswer
     }
 
     /** Implements [UniqueParameterType.TerrainFilter][com.unciv.models.ruleset.unique.UniqueParameterType.TerrainFilter] */