diff --git a/modules/rule/src/main/scala/de/nowchess/rules/RuleSet.scala b/modules/api/src/main/scala/de/nowchess/api/rules/RuleSet.scala
similarity index 98%
rename from modules/rule/src/main/scala/de/nowchess/rules/RuleSet.scala
rename to modules/api/src/main/scala/de/nowchess/api/rules/RuleSet.scala
index f2622bd..535b655 100644
--- a/modules/rule/src/main/scala/de/nowchess/rules/RuleSet.scala
+++ b/modules/api/src/main/scala/de/nowchess/api/rules/RuleSet.scala
@@ -1,7 +1,7 @@
-package de.nowchess.rules
+package de.nowchess.api.rules
 
-import de.nowchess.api.game.GameContext
 import de.nowchess.api.board.Square
+import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.Move
 
 /** Extension point for chess rule variants (standard, Chess960, etc.). All rule queries are stateless: given a
diff --git a/modules/bot/src/main/scala/de/nowchess/bot/bots/ClassicalBot.scala b/modules/bot/src/main/scala/de/nowchess/bot/bots/ClassicalBot.scala
index 0573110..a52e5b9 100644
--- a/modules/bot/src/main/scala/de/nowchess/bot/bots/ClassicalBot.scala
+++ b/modules/bot/src/main/scala/de/nowchess/bot/bots/ClassicalBot.scala
@@ -7,7 +7,7 @@ import de.nowchess.bot.bots.classic.EvaluationClassic
 import de.nowchess.bot.logic.AlphaBetaSearch
 import de.nowchess.bot.util.PolyglotBook
 import de.nowchess.bot.{BotDifficulty, BotMoveRepetition}
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 import de.nowchess.rules.sets.DefaultRules
 
 final class ClassicalBot(
diff --git a/modules/bot/src/main/scala/de/nowchess/bot/bots/HybridBot.scala b/modules/bot/src/main/scala/de/nowchess/bot/bots/HybridBot.scala
index 3a9147a..fd95d0d 100644
--- a/modules/bot/src/main/scala/de/nowchess/bot/bots/HybridBot.scala
+++ b/modules/bot/src/main/scala/de/nowchess/bot/bots/HybridBot.scala
@@ -9,7 +9,7 @@ import de.nowchess.bot.bots.nnue.EvaluationNNUE
 import de.nowchess.bot.logic.{AlphaBetaSearch, TranspositionTable}
 import de.nowchess.bot.util.PolyglotBook
 import de.nowchess.bot.{BotDifficulty, BotMoveRepetition, Config}
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 import de.nowchess.rules.sets.DefaultRules
 
 final class HybridBot(
diff --git a/modules/bot/src/main/scala/de/nowchess/bot/bots/NNUEBot.scala b/modules/bot/src/main/scala/de/nowchess/bot/bots/NNUEBot.scala
index 094989d..bfa2c6f 100644
--- a/modules/bot/src/main/scala/de/nowchess/bot/bots/NNUEBot.scala
+++ b/modules/bot/src/main/scala/de/nowchess/bot/bots/NNUEBot.scala
@@ -7,7 +7,7 @@ import de.nowchess.bot.bots.nnue.EvaluationNNUE
 import de.nowchess.bot.logic.AlphaBetaSearch
 import de.nowchess.bot.util.{PolyglotBook, ZobristHash}
 import de.nowchess.bot.{BotDifficulty, BotMoveRepetition}
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 import de.nowchess.rules.sets.DefaultRules
 
 final class NNUEBot(
diff --git a/modules/bot/src/main/scala/de/nowchess/bot/logic/AlphaBetaSearch.scala b/modules/bot/src/main/scala/de/nowchess/bot/logic/AlphaBetaSearch.scala
index 8a58b21..cf41d70 100644
--- a/modules/bot/src/main/scala/de/nowchess/bot/logic/AlphaBetaSearch.scala
+++ b/modules/bot/src/main/scala/de/nowchess/bot/logic/AlphaBetaSearch.scala
@@ -5,7 +5,7 @@ import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType}
 import de.nowchess.bot.ai.Evaluation
 import de.nowchess.bot.util.ZobristHash
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 import de.nowchess.rules.sets.DefaultRules
 import java.util.concurrent.atomic.{AtomicInteger, AtomicLong}
 
diff --git a/modules/bot/src/test/scala/de/nowchess/bot/AlphaBetaSearchTest.scala b/modules/bot/src/test/scala/de/nowchess/bot/AlphaBetaSearchTest.scala
index 609f977..da826bd 100644
--- a/modules/bot/src/test/scala/de/nowchess/bot/AlphaBetaSearchTest.scala
+++ b/modules/bot/src/test/scala/de/nowchess/bot/AlphaBetaSearchTest.scala
@@ -6,7 +6,7 @@ import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
 import de.nowchess.bot.ai.Evaluation
 import de.nowchess.bot.bots.classic.EvaluationClassic
 import de.nowchess.bot.logic.AlphaBetaSearch
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers
 import de.nowchess.rules.sets.DefaultRules
diff --git a/modules/bot/src/test/scala/de/nowchess/bot/ClassicalBotTest.scala b/modules/bot/src/test/scala/de/nowchess/bot/ClassicalBotTest.scala
index 30b0214..bf53263 100644
--- a/modules/bot/src/test/scala/de/nowchess/bot/ClassicalBotTest.scala
+++ b/modules/bot/src/test/scala/de/nowchess/bot/ClassicalBotTest.scala
@@ -5,7 +5,7 @@ import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.Move
 import de.nowchess.api.move.MoveType
 import de.nowchess.bot.bots.ClassicalBot
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers
 import de.nowchess.rules.sets.DefaultRules
diff --git a/modules/bot/src/test/scala/de/nowchess/bot/HybridBotTest.scala b/modules/bot/src/test/scala/de/nowchess/bot/HybridBotTest.scala
index b1e7e81..bf806c2 100644
--- a/modules/bot/src/test/scala/de/nowchess/bot/HybridBotTest.scala
+++ b/modules/bot/src/test/scala/de/nowchess/bot/HybridBotTest.scala
@@ -6,7 +6,7 @@ import de.nowchess.api.move.{Move, MoveType}
 import de.nowchess.bot.ai.Evaluation
 import de.nowchess.bot.bots.HybridBot
 import de.nowchess.bot.util.{PolyglotBook, PolyglotHash}
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers
 
diff --git a/modules/core/build.gradle.kts b/modules/core/build.gradle.kts
index d572500..f6b2c8b 100644
--- a/modules/core/build.gradle.kts
+++ b/modules/core/build.gradle.kts
@@ -49,7 +49,7 @@ dependencies {
 
     implementation(project(":modules:api"))
     implementation(project(":modules:io"))
-    implementation(project(":modules:rule"))
+    testImplementation(project(":modules:rule"))
     implementation(project(":modules:bot"))
 
 
diff --git a/modules/core/src/main/resources/application.yml b/modules/core/src/main/resources/application.yml
index 1663bc0..bbc7bff 100644
--- a/modules/core/src/main/resources/application.yml
+++ b/modules/core/src/main/resources/application.yml
@@ -6,3 +6,5 @@ quarkus:
   rest-client:
     io-service:
       url: http://localhost:8081
+    rule-service:
+      url: http://localhost:8082
diff --git a/modules/core/src/main/scala/de/nowchess/chess/adapter/RuleSetRestAdapter.scala b/modules/core/src/main/scala/de/nowchess/chess/adapter/RuleSetRestAdapter.scala
new file mode 100644
index 0000000..a281095
--- /dev/null
+++ b/modules/core/src/main/scala/de/nowchess/chess/adapter/RuleSetRestAdapter.scala
@@ -0,0 +1,51 @@
+package de.nowchess.chess.adapter
+
+import de.nowchess.api.board.Square
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.move.Move
+import de.nowchess.chess.client.{RuleMoveRequest, RuleServiceClient, RuleSquareRequest}
+import de.nowchess.api.rules.RuleSet
+import jakarta.enterprise.context.ApplicationScoped
+import jakarta.inject.Inject
+import org.eclipse.microprofile.rest.client.inject.RestClient
+
+import scala.compiletime.uninitialized
+
+@ApplicationScoped
+class RuleSetRestAdapter extends RuleSet:
+
+  // scalafix:off DisableSyntax.var
+  @Inject
+  @RestClient
+  var client: RuleServiceClient = uninitialized
+  // scalafix:on DisableSyntax.var
+
+  def candidateMoves(ctx: GameContext)(sq: Square): List[Move] =
+    client.candidateMoves(RuleSquareRequest(ctx, sq.toString))
+
+  def legalMoves(ctx: GameContext)(sq: Square): List[Move] =
+    client.legalMoves(RuleSquareRequest(ctx, sq.toString))
+
+  def allLegalMoves(ctx: GameContext): List[Move] =
+    client.allLegalMoves(ctx)
+
+  def isCheck(ctx: GameContext): Boolean =
+    client.isCheck(ctx)
+
+  def isCheckmate(ctx: GameContext): Boolean =
+    client.isCheckmate(ctx)
+
+  def isStalemate(ctx: GameContext): Boolean =
+    client.isStalemate(ctx)
+
+  def isInsufficientMaterial(ctx: GameContext): Boolean =
+    client.isInsufficientMaterial(ctx)
+
+  def isFiftyMoveRule(ctx: GameContext): Boolean =
+    client.isFiftyMoveRule(ctx)
+
+  def isThreefoldRepetition(ctx: GameContext): Boolean =
+    client.isThreefoldRepetition(ctx)
+
+  def applyMove(ctx: GameContext)(move: Move): GameContext =
+    client.applyMove(RuleMoveRequest(ctx, move))
diff --git a/modules/core/src/main/scala/de/nowchess/chess/client/RuleServiceClient.scala b/modules/core/src/main/scala/de/nowchess/chess/client/RuleServiceClient.scala
new file mode 100644
index 0000000..b213ef4
--- /dev/null
+++ b/modules/core/src/main/scala/de/nowchess/chess/client/RuleServiceClient.scala
@@ -0,0 +1,74 @@
+package de.nowchess.chess.client
+
+import de.nowchess.api.game.GameContext
+import de.nowchess.api.move.Move
+import jakarta.ws.rs.*
+import jakarta.ws.rs.core.MediaType
+import org.eclipse.microprofile.rest.client.inject.RegisterRestClient
+
+case class RuleSquareRequest(context: GameContext, square: String)
+case class RuleMoveRequest(context: GameContext, move: Move)
+
+@Path("/api/rules")
+@RegisterRestClient(configKey = "rule-service")
+trait RuleServiceClient:
+
+  @POST
+  @Path("/candidate-moves")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def candidateMoves(req: RuleSquareRequest): List[Move]
+
+  @POST
+  @Path("/legal-moves")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def legalMoves(req: RuleSquareRequest): List[Move]
+
+  @POST
+  @Path("/all-legal-moves")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def allLegalMoves(ctx: GameContext): List[Move]
+
+  @POST
+  @Path("/is-check")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def isCheck(ctx: GameContext): Boolean
+
+  @POST
+  @Path("/is-checkmate")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def isCheckmate(ctx: GameContext): Boolean
+
+  @POST
+  @Path("/is-stalemate")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def isStalemate(ctx: GameContext): Boolean
+
+  @POST
+  @Path("/is-insufficient-material")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def isInsufficientMaterial(ctx: GameContext): Boolean
+
+  @POST
+  @Path("/is-fifty-move-rule")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def isFiftyMoveRule(ctx: GameContext): Boolean
+
+  @POST
+  @Path("/is-threefold-repetition")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def isThreefoldRepetition(ctx: GameContext): Boolean
+
+  @POST
+  @Path("/apply-move")
+  @Consumes(Array(MediaType.APPLICATION_JSON))
+  @Produces(Array(MediaType.APPLICATION_JSON))
+  def applyMove(req: RuleMoveRequest): GameContext
diff --git a/modules/core/src/main/scala/de/nowchess/chess/config/JacksonConfig.scala b/modules/core/src/main/scala/de/nowchess/chess/config/JacksonConfig.scala
index 816cb0b..254368d 100644
--- a/modules/core/src/main/scala/de/nowchess/chess/config/JacksonConfig.scala
+++ b/modules/core/src/main/scala/de/nowchess/chess/config/JacksonConfig.scala
@@ -5,6 +5,8 @@ import com.fasterxml.jackson.databind.ObjectMapper
 import com.fasterxml.jackson.databind.module.SimpleModule
 import com.fasterxml.jackson.module.scala.DefaultScalaModule
 import de.nowchess.api.board.Square
+import de.nowchess.api.move.MoveType
+import de.nowchess.chess.json.{MoveTypeDeserializer, MoveTypeSerializer, SquareDeserializer, SquareSerializer}
 import de.nowchess.io.json.{SquareKeyDeserializer, SquareKeySerializer}
 import io.quarkus.jackson.ObjectMapperCustomizer
 import jakarta.inject.Singleton
@@ -18,7 +20,11 @@ class JacksonConfig extends ObjectMapperCustomizer:
         new Version(2, 21, 1, null, "com.fasterxml.jackson.module", "jackson-module-scala")
         // scalafix:on DisableSyntax.null
     })
-    val squareModule = new SimpleModule()
-    squareModule.addKeyDeserializer(classOf[Square], new SquareKeyDeserializer())
-    squareModule.addKeySerializer(classOf[Square], new SquareKeySerializer())
-    mapper.registerModule(squareModule)
+    val mod = new SimpleModule()
+    mod.addKeySerializer(classOf[Square], new SquareKeySerializer())
+    mod.addKeyDeserializer(classOf[Square], new SquareKeyDeserializer())
+    mod.addSerializer(classOf[Square], new SquareSerializer())
+    mod.addDeserializer(classOf[Square], new SquareDeserializer())
+    mod.addSerializer(classOf[MoveType], new MoveTypeSerializer())
+    mod.addDeserializer(classOf[MoveType], new MoveTypeDeserializer())
+    mapper.registerModule(mod)
diff --git a/modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala b/modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala
index 43f099b..43ac4fa 100644
--- a/modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala
+++ b/modules/core/src/main/scala/de/nowchess/chess/engine/GameEngine.scala
@@ -8,8 +8,7 @@ import de.nowchess.chess.controller.Parser
 import de.nowchess.chess.observer.*
 import de.nowchess.chess.command.{CommandInvoker, MoveCommand, MoveResult}
 import de.nowchess.io.{GameContextExport, GameContextImport}
-import de.nowchess.rules.RuleSet
-import de.nowchess.rules.sets.DefaultRules
+import de.nowchess.api.rules.RuleSet
 
 import scala.concurrent.{ExecutionContext, Future}
 
@@ -18,7 +17,7 @@ import scala.concurrent.{ExecutionContext, Future}
   */
 class GameEngine(
     val initialContext: GameContext = GameContext.initial,
-    val ruleSet: RuleSet = DefaultRules,
+    val ruleSet: RuleSet,
     val participants: Map[Color, Participant] = Map(
       Color.White -> Human(PlayerInfo(PlayerId("p1"), "Player 1")),
       Color.Black -> Human(PlayerInfo(PlayerId("p2"), "Player 2")),
diff --git a/modules/core/src/main/scala/de/nowchess/chess/json/MoveTypeDeserializer.scala b/modules/core/src/main/scala/de/nowchess/chess/json/MoveTypeDeserializer.scala
new file mode 100644
index 0000000..969d614
--- /dev/null
+++ b/modules/core/src/main/scala/de/nowchess/chess/json/MoveTypeDeserializer.scala
@@ -0,0 +1,19 @@
+package de.nowchess.chess.json
+
+import com.fasterxml.jackson.core.{JsonParseException, JsonParser}
+import com.fasterxml.jackson.databind.node.ObjectNode
+import com.fasterxml.jackson.databind.{DeserializationContext, JsonDeserializer}
+import de.nowchess.api.move.{MoveType, PromotionPiece}
+
+class MoveTypeDeserializer extends JsonDeserializer[MoveType]:
+  // scalafix:off DisableSyntax.throw
+  override def deserialize(p: JsonParser, ctx: DeserializationContext): MoveType =
+    val node = p.getCodec.readTree[ObjectNode](p)
+    node.get("type").asText() match
+      case "normal"          => MoveType.Normal(node.get("isCapture").asBoolean(false))
+      case "castleKingside"  => MoveType.CastleKingside
+      case "castleQueenside" => MoveType.CastleQueenside
+      case "enPassant"       => MoveType.EnPassant
+      case "promotion"       => MoveType.Promotion(PromotionPiece.valueOf(node.get("piece").asText()))
+      case t                 => throw new JsonParseException(p, s"Unknown move type: $t")
+  // scalafix:on DisableSyntax.throw
diff --git a/modules/core/src/main/scala/de/nowchess/chess/json/MoveTypeSerializer.scala b/modules/core/src/main/scala/de/nowchess/chess/json/MoveTypeSerializer.scala
new file mode 100644
index 0000000..8d90eba
--- /dev/null
+++ b/modules/core/src/main/scala/de/nowchess/chess/json/MoveTypeSerializer.scala
@@ -0,0 +1,23 @@
+package de.nowchess.chess.json
+
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.databind.{JsonSerializer, SerializerProvider}
+import de.nowchess.api.move.MoveType
+
+class MoveTypeSerializer extends JsonSerializer[MoveType]:
+  override def serialize(value: MoveType, gen: JsonGenerator, provider: SerializerProvider): Unit =
+    gen.writeStartObject()
+    value match
+      case MoveType.Normal(isCapture) =>
+        gen.writeStringField("type", "normal")
+        gen.writeBooleanField("isCapture", isCapture)
+      case MoveType.CastleKingside =>
+        gen.writeStringField("type", "castleKingside")
+      case MoveType.CastleQueenside =>
+        gen.writeStringField("type", "castleQueenside")
+      case MoveType.EnPassant =>
+        gen.writeStringField("type", "enPassant")
+      case MoveType.Promotion(piece) =>
+        gen.writeStringField("type", "promotion")
+        gen.writeStringField("piece", piece.toString)
+    gen.writeEndObject()
diff --git a/modules/core/src/main/scala/de/nowchess/chess/json/SquareDeserializer.scala b/modules/core/src/main/scala/de/nowchess/chess/json/SquareDeserializer.scala
new file mode 100644
index 0000000..a14b84f
--- /dev/null
+++ b/modules/core/src/main/scala/de/nowchess/chess/json/SquareDeserializer.scala
@@ -0,0 +1,11 @@
+package de.nowchess.chess.json
+
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.{DeserializationContext, JsonDeserializer}
+import de.nowchess.api.board.Square
+
+class SquareDeserializer extends JsonDeserializer[Square]:
+  // scalafix:off DisableSyntax.null
+  override def deserialize(p: JsonParser, ctx: DeserializationContext): Square =
+    Square.fromAlgebraic(p.getText).orNull
+  // scalafix:on DisableSyntax.null
diff --git a/modules/core/src/main/scala/de/nowchess/chess/json/SquareSerializer.scala b/modules/core/src/main/scala/de/nowchess/chess/json/SquareSerializer.scala
new file mode 100644
index 0000000..98240ac
--- /dev/null
+++ b/modules/core/src/main/scala/de/nowchess/chess/json/SquareSerializer.scala
@@ -0,0 +1,9 @@
+package de.nowchess.chess.json
+
+import com.fasterxml.jackson.core.JsonGenerator
+import com.fasterxml.jackson.databind.{JsonSerializer, SerializerProvider}
+import de.nowchess.api.board.Square
+
+class SquareSerializer extends JsonSerializer[Square]:
+  override def serialize(value: Square, gen: JsonGenerator, provider: SerializerProvider): Unit =
+    gen.writeString(value.toString)
diff --git a/modules/core/src/main/scala/de/nowchess/chess/resource/GameResource.scala b/modules/core/src/main/scala/de/nowchess/chess/resource/GameResource.scala
index 654e303..e050fb7 100644
--- a/modules/core/src/main/scala/de/nowchess/chess/resource/GameResource.scala
+++ b/modules/core/src/main/scala/de/nowchess/chess/resource/GameResource.scala
@@ -6,6 +6,7 @@ import de.nowchess.api.dto.*
 import de.nowchess.api.game.{DrawReason, GameContext, GameResult}
 import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
 import de.nowchess.api.player.{PlayerId, PlayerInfo}
+import de.nowchess.chess.adapter.RuleSetRestAdapter
 import de.nowchess.chess.client.IoServiceClient
 import de.nowchess.chess.controller.Parser
 import de.nowchess.chess.engine.GameEngine
@@ -39,6 +40,9 @@ class GameResource:
   @Inject
   @RestClient
   var ioClient: IoServiceClient = uninitialized
+
+  @Inject
+  var ruleSetAdapter: RuleSetRestAdapter = uninitialized
   // scalafix:on DisableSyntax.var
 
   private val DefaultWhite = PlayerInfo(PlayerId("p1"), "Player 1")
@@ -114,7 +118,7 @@ class GameResource:
     dto.fold(default)(d => PlayerInfo(PlayerId(d.id), d.displayName))
 
   private def newEntry(ctx: GameContext, white: PlayerInfo, black: PlayerInfo): GameEntry =
-    GameEntry(registry.generateId(), GameEngine(initialContext = ctx), white, black)
+    GameEntry(registry.generateId(), GameEngine(initialContext = ctx, ruleSet = ruleSetAdapter), white, black)
 
   private def applyMoveInput(engine: GameEngine, uci: String): Option[String] =
     val error = new AtomicReference[Option[String]](None)
diff --git a/modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala b/modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala
index 3a32668..7c49e73 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/engine/EngineTestHelpers.scala
@@ -13,7 +13,7 @@ object EngineTestHelpers:
     new GameEngine(ruleSet = DefaultRules)
 
   def makeEngineWithBoard(board: Board, turn: Color = Color.White): GameEngine =
-    GameEngine(initialContext = GameContext.initial.withBoard(board).withTurn(turn))
+    GameEngine(initialContext = GameContext.initial.withBoard(board).withTurn(turn), ruleSet = DefaultRules)
 
   def loadFen(engine: GameEngine, fen: String): Unit =
     engine.loadGame(FenParser, fen)
diff --git a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineDrawOfferTest.scala b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineDrawOfferTest.scala
index 03b39a6..872ce56 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineDrawOfferTest.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineDrawOfferTest.scala
@@ -1,5 +1,6 @@
 package de.nowchess.chess.engine
 
+import de.nowchess.rules.sets.DefaultRules
 import scala.collection.mutable
 import de.nowchess.api.board.Color
 import de.nowchess.api.game.{DrawReason, GameResult}
@@ -18,7 +19,7 @@ import org.scalatest.matchers.should.Matchers
 class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
 
   test("White offers draw"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -32,7 +33,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected DrawOfferEvent, but got $other")
 
   test("Black accepts White's draw offer"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -49,7 +50,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected DrawEvent, but got $other")
 
   test("Black declines White's draw offer"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -65,7 +66,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected DrawOfferDeclinedEvent, but got $other")
 
   test("Black offers draw"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -79,7 +80,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected DrawOfferEvent, but got $other")
 
   test("White accepts Black's draw offer"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -96,7 +97,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected DrawEvent, but got $other")
 
   test("Cannot accept draw when no offer pending"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -110,7 +111,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected InvalidMoveEvent, but got $other")
 
   test("Cannot decline draw when no offer pending"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -124,7 +125,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected InvalidMoveEvent, but got $other")
 
   test("Cannot offer draw when game is already over"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -147,7 +148,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected InvalidMoveEvent, but got $other")
 
   test("Cannot accept your own draw offer"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -163,7 +164,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected InvalidMoveEvent, but got $other")
 
   test("Cannot decline your own draw offer"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -179,7 +180,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected InvalidMoveEvent, but got $other")
 
   test("Cannot make second draw offer when one is already pending"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -195,7 +196,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected InvalidMoveEvent, but got $other")
 
   test("Draw offer is cleared when game ends by resignation (accept)"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -215,7 +216,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected InvalidMoveEvent, but got $other")
 
   test("Draw offer is cleared when game ends by resignation (decline)"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
 
@@ -235,22 +236,22 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected InvalidMoveEvent, but got $other")
 
   test("pendingDrawOfferBy returns None initially"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     engine.pendingDrawOfferBy shouldBe None
 
   test("pendingDrawOfferBy returns White after White offers"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     engine.offerDraw(Color.White)
     engine.pendingDrawOfferBy shouldBe Some(Color.White)
 
   test("pendingDrawOfferBy returns None after draw is accepted"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     engine.offerDraw(Color.White)
     engine.acceptDraw(Color.Black)
     engine.pendingDrawOfferBy shouldBe None
 
   test("applyDraw sets draw result when game not over"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
     engine.applyDraw(DrawReason.Agreement)
@@ -263,7 +264,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
         fail(s"Expected DrawEvent, but got $other")
 
   test("applyDraw does nothing when game already over"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
     // End the game with checkmate
@@ -276,7 +277,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
     observer.events should have length 0
 
   test("claimDraw with fifty-move rule when at half-move 100"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
     // Play moves to reach fifty-move rule claim
@@ -288,7 +289,7 @@ class GameEngineDrawOfferTest extends AnyFunSuite with Matchers:
     // This is hard to do naturally; skip for now if not critical
 
   test("claimDraw when game already over"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new DrawOfferMockObserver()
     engine.subscribe(observer)
     // End the game with checkmate
diff --git a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineGameEndingTest.scala b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineGameEndingTest.scala
index 9e491e8..4bb9207 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineGameEndingTest.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineGameEndingTest.scala
@@ -1,5 +1,6 @@
 package de.nowchess.chess.engine
 
+import de.nowchess.rules.sets.DefaultRules
 import scala.collection.mutable
 import de.nowchess.api.board.Color
 import de.nowchess.api.game.DrawReason
@@ -11,7 +12,7 @@ import org.scalatest.matchers.should.Matchers
 class GameEngineGameEndingTest extends AnyFunSuite with Matchers:
 
   test("GameEngine handles Checkmate (Fool's Mate)"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new EndingMockObserver()
     engine.subscribe(observer)
 
@@ -31,7 +32,7 @@ class GameEngineGameEndingTest extends AnyFunSuite with Matchers:
         fail(s"Expected CheckmateEvent, but got $other")
 
   test("GameEngine handles check detection"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new EndingMockObserver()
     engine.subscribe(observer)
 
@@ -53,7 +54,7 @@ class GameEngineGameEndingTest extends AnyFunSuite with Matchers:
   // Wait, let's just use Sam Loyd's 10-move stalemate:
   // 1. e3 a5 2. Qh5 Ra6 3. Qxa5 h5 4. h4 Rah6 5. Qxc7 f6 6. Qxd7+ Kf7 7. Qxb7 Qd3 8. Qxb8 Qh7 9. Qxc8 Kg6 10. Qe6
   test("GameEngine handles Stalemate via 10-move known sequence"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new EndingMockObserver()
     engine.subscribe(observer)
 
diff --git a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala
index 371f2dd..d4586f6 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineIntegrationTest.scala
@@ -5,7 +5,7 @@ import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
 import de.nowchess.chess.observer.{GameEvent, InvalidMoveEvent, InvalidMoveReason, MoveRedoneEvent, Observer}
 import de.nowchess.io.GameContextImport
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 import de.nowchess.rules.sets.DefaultRules
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers
@@ -21,7 +21,7 @@ class GameEngineIntegrationTest extends AnyFunSuite with Matchers:
     events
 
   test("accessors expose redo availability and command history"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
 
     engine.canRedo shouldBe false
     engine.commandHistory shouldBe empty
@@ -30,7 +30,7 @@ class GameEngineIntegrationTest extends AnyFunSuite with Matchers:
     engine.commandHistory.nonEmpty shouldBe true
 
   test("processUserInput handles undo redo empty and malformed commands"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val events = captureEvents(engine)
 
     engine.processUserInput("")
@@ -44,7 +44,7 @@ class GameEngineIntegrationTest extends AnyFunSuite with Matchers:
     } should be >= 3
 
   test("processUserInput emits Illegal move for syntactically valid but illegal target"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val events = captureEvents(engine)
 
     engine.processUserInput("e2e5")
@@ -56,14 +56,14 @@ class GameEngineIntegrationTest extends AnyFunSuite with Matchers:
 
   test("loadGame returns Left when importer fails"):
 
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val failingImporter = new GameContextImport:
       def importGameContext(input: String): Either[String, GameContext] = Left("boom")
 
     engine.loadGame(failingImporter, "ignored") shouldBe Left("boom")
 
   test("loadPosition replaces context clears history and notifies reset"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val events = captureEvents(engine)
 
     engine.processUserInput("e2e4")
@@ -78,7 +78,7 @@ class GameEngineIntegrationTest extends AnyFunSuite with Matchers:
     } shouldBe true
 
   test("redo event includes captured piece description when replaying a capture"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val events = captureEvents(engine)
 
     EngineTestHelpers.loadFen(engine, "4k3/8/8/8/8/8/4K3/R6r w - - 0 1")
@@ -145,13 +145,13 @@ class GameEngineIntegrationTest extends AnyFunSuite with Matchers:
 
   test("loadGame replay executes non-promotion moves through default replay branch"):
     val normalMove = Move(sq("e2"), sq("e4"), MoveType.Normal())
-    val engine     = new GameEngine()
+    val engine     = new GameEngine(ruleSet = DefaultRules)
 
     engine.replayMoves(List(normalMove), engine.context) shouldBe Right(())
     engine.context.moves.lastOption shouldBe Some(normalMove)
 
   test("replayMoves skips later moves after the first move triggers an error"):
-    val engine           = new GameEngine()
+    val engine           = new GameEngine(ruleSet = DefaultRules)
     val saved            = engine.context
     val illegalPromotion = Move(sq("e2"), sq("e1"), MoveType.Promotion(PromotionPiece.Queen))
     val trailingMove     = Move(sq("e2"), sq("e4"))
@@ -160,19 +160,19 @@ class GameEngineIntegrationTest extends AnyFunSuite with Matchers:
     engine.context shouldBe saved
 
   test("normalMoveNotation handles missing source piece"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val result = engine.normalMoveNotation(Move(sq("e3"), sq("e4")), Board.initial, isCapture = false)
 
     result shouldBe "e4"
 
   test("pieceNotation default branch returns empty string"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val result = engine.pieceNotation(PieceType.Pawn)
 
     result shouldBe ""
 
   test("observerCount reflects subscribe and unsubscribe operations"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val observer = new Observer:
       def onGameEvent(event: GameEvent): Unit = ()
 
diff --git a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineLoadGameTest.scala b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineLoadGameTest.scala
index d926147..c3b6a50 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineLoadGameTest.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineLoadGameTest.scala
@@ -1,5 +1,6 @@
 package de.nowchess.chess.engine
 
+import de.nowchess.rules.sets.DefaultRules
 import scala.collection.mutable
 import de.nowchess.api.board.{Board, Color}
 import de.nowchess.api.game.GameContext
@@ -14,7 +15,7 @@ import org.scalatest.matchers.should.Matchers
 class GameEngineLoadGameTest extends AnyFunSuite with Matchers:
 
   test("loadGame with PgnParser: loads valid PGN and enables undo/redo"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val pgn    = "[Event \"Test\"]\n\n1. e4 e5\n"
     val result = engine.loadGame(PgnParser, pgn)
     result shouldBe Right(())
@@ -22,7 +23,7 @@ class GameEngineLoadGameTest extends AnyFunSuite with Matchers:
     engine.canUndo shouldBe true
 
   test("loadGame with FenParser: loads position without replaying moves"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     val fen    = "8/4P3/4k3/8/8/8/8/8 w - - 0 1"
     val result = engine.loadGame(FenParser, fen)
     result shouldBe Right(())
@@ -30,7 +31,7 @@ class GameEngineLoadGameTest extends AnyFunSuite with Matchers:
     engine.canUndo shouldBe false
 
   test("exportGame with PgnExporter: exports current game as PGN"):
-    val engine = new GameEngine()
+    val engine = new GameEngine(ruleSet = DefaultRules)
     engine.processUserInput("e2e4")
     engine.processUserInput("e7e5")
     val pgn = engine.exportGame(PgnExporter)
diff --git a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineNotationTest.scala b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineNotationTest.scala
index e1c1877..6482b35 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineNotationTest.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineNotationTest.scala
@@ -1,6 +1,7 @@
 package de.nowchess.chess.engine
 
 import de.nowchess.api.board.{Board, Color, File, Rank, Square}
+import de.nowchess.rules.sets.DefaultRules
 import de.nowchess.api.game.GameContext
 import de.nowchess.io.fen.FenParser
 import de.nowchess.chess.observer.*
@@ -37,7 +38,7 @@ class GameEngineNotationTest extends AnyFunSuite with Matchers:
       .withTurn(Color.White)
       .withCastlingRights(castlingRights)
 
-    val engine = new GameEngine(ctx)
+    val engine = new GameEngine(ctx, DefaultRules)
     val events = captureEvents(engine)
 
     // White castles queenside: e1c1
@@ -65,7 +66,7 @@ class GameEngineNotationTest extends AnyFunSuite with Matchers:
       .withEnPassantSquare(epSquare)
       .withCastlingRights(de.nowchess.api.board.CastlingRights(false, false, false, false))
 
-    val engine = new GameEngine(ctx)
+    val engine = new GameEngine(ctx, DefaultRules)
     val events = captureEvents(engine)
 
     // White pawn on e5 captures en passant to d6
@@ -96,7 +97,7 @@ class GameEngineNotationTest extends AnyFunSuite with Matchers:
       .withTurn(Color.White)
       .withCastlingRights(de.nowchess.api.board.CastlingRights(false, false, false, false))
 
-    val engine = new GameEngine(ctx)
+    val engine = new GameEngine(ctx, DefaultRules)
     val events = captureEvents(engine)
 
     engine.processUserInput("e7e8b")
@@ -117,7 +118,7 @@ class GameEngineNotationTest extends AnyFunSuite with Matchers:
       .withTurn(Color.White)
       .withCastlingRights(de.nowchess.api.board.CastlingRights(false, false, false, false))
 
-    val engine = new GameEngine(ctx)
+    val engine = new GameEngine(ctx, DefaultRules)
     val events = captureEvents(engine)
 
     // King moves e1 -> f1
diff --git a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala
index 4c86f17..edc74d7 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEnginePromotionTest.scala
@@ -14,7 +14,7 @@ import de.nowchess.chess.observer.{
   MoveExecutedEvent,
   Observer,
 }
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 import de.nowchess.rules.sets.DefaultRules
 import org.scalatest.funsuite.AnyFunSuite
 import org.scalatest.matchers.should.Matchers
@@ -29,7 +29,7 @@ class GameEnginePromotionTest extends AnyFunSuite with Matchers:
     events
 
   private def engineWith(board: Board, turn: Color = Color.White): GameEngine =
-    new GameEngine(initialContext = GameContext.initial.withBoard(board).withTurn(turn))
+    new GameEngine(initialContext = GameContext.initial.withBoard(board).withTurn(turn), ruleSet = DefaultRules)
 
   test("processUserInput without promotion suffix fires InvalidMoveEvent when pawn reaches back rank") {
     val promotionBoard = FenParser.parseBoard("8/4P3/4k3/8/8/8/8/8").get
diff --git a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineResignTest.scala b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineResignTest.scala
index cf96cdf..0ee4395 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineResignTest.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/engine/GameEngineResignTest.scala
@@ -1,5 +1,6 @@
 package de.nowchess.chess.engine
 
+import de.nowchess.rules.sets.DefaultRules
 import scala.collection.mutable
 import de.nowchess.api.board.Color
 import de.nowchess.api.game.GameResult
@@ -10,7 +11,7 @@ import org.scalatest.matchers.should.Matchers
 class GameEngineResignTest extends AnyFunSuite with Matchers:
 
   test("White resigns"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new ResignMockObserver()
     engine.subscribe(observer)
 
@@ -25,7 +26,7 @@ class GameEngineResignTest extends AnyFunSuite with Matchers:
         fail(s"Expected ResignEvent, but got $other")
 
   test("Black resigns"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new ResignMockObserver()
     engine.subscribe(observer)
 
@@ -40,7 +41,7 @@ class GameEngineResignTest extends AnyFunSuite with Matchers:
         fail(s"Expected ResignEvent, but got $other")
 
   test("Cannot resign when game is already over"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new ResignMockObserver()
     engine.subscribe(observer)
 
@@ -64,7 +65,7 @@ class GameEngineResignTest extends AnyFunSuite with Matchers:
         fail(s"Expected InvalidMoveEvent, but got $other")
 
   test("resign() without color resigns side to move"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new ResignMockObserver()
     engine.subscribe(observer)
 
@@ -73,7 +74,7 @@ class GameEngineResignTest extends AnyFunSuite with Matchers:
     engine.context.result shouldBe Some(GameResult.Win(Color.Black))
 
   test("resign() without color does nothing when game already over"):
-    val engine   = new GameEngine()
+    val engine   = new GameEngine(ruleSet = DefaultRules)
     val observer = new ResignMockObserver()
     engine.subscribe(observer)
 
diff --git a/modules/core/src/test/scala/de/nowchess/chess/registry/GameRegistryImplTest.scala b/modules/core/src/test/scala/de/nowchess/chess/registry/GameRegistryImplTest.scala
index 6bea0c0..f027e53 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/registry/GameRegistryImplTest.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/registry/GameRegistryImplTest.scala
@@ -1,6 +1,7 @@
 package de.nowchess.chess.registry
 
 import de.nowchess.api.player.{PlayerId, PlayerInfo}
+import de.nowchess.rules.sets.DefaultRules
 import de.nowchess.chess.engine.GameEngine
 import io.quarkus.test.junit.QuarkusTest
 import jakarta.inject.Inject
@@ -20,14 +21,14 @@ class GameRegistryImplTest:
   @Test
   @DisplayName("store saves entry")
   def testStore(): Unit =
-    val entry = GameEntry("g1", GameEngine(), PlayerInfo(PlayerId("p1"), "P1"), PlayerInfo(PlayerId("p2"), "P2"))
+    val entry = GameEntry("g1", GameEngine(ruleSet = DefaultRules), PlayerInfo(PlayerId("p1"), "P1"), PlayerInfo(PlayerId("p2"), "P2"))
     registry.store(entry)
     assertTrue(registry.get("g1").isDefined)
 
   @Test
   @DisplayName("get returns stored entry")
   def testGet(): Unit =
-    val entry = GameEntry("g2", GameEngine(), PlayerInfo(PlayerId("p1"), "P1"), PlayerInfo(PlayerId("p2"), "P2"))
+    val entry = GameEntry("g2", GameEngine(ruleSet = DefaultRules), PlayerInfo(PlayerId("p1"), "P1"), PlayerInfo(PlayerId("p2"), "P2"))
     registry.store(entry)
     val retrieved = registry.get("g2")
     assertTrue(retrieved.isDefined)
@@ -41,7 +42,7 @@ class GameRegistryImplTest:
   @Test
   @DisplayName("update modifies existing entry")
   def testUpdate(): Unit =
-    val entry = GameEntry("g3", GameEngine(), PlayerInfo(PlayerId("p1"), "P1"), PlayerInfo(PlayerId("p2"), "P2"))
+    val entry = GameEntry("g3", GameEngine(ruleSet = DefaultRules), PlayerInfo(PlayerId("p1"), "P1"), PlayerInfo(PlayerId("p2"), "P2"))
     registry.store(entry)
     val updated = entry.copy(resigned = true)
     registry.update(updated)
diff --git a/modules/core/src/test/scala/de/nowchess/chess/resource/GameResourceIntegrationTest.scala b/modules/core/src/test/scala/de/nowchess/chess/resource/GameResourceIntegrationTest.scala
index 1ee458e..abea233 100644
--- a/modules/core/src/test/scala/de/nowchess/chess/resource/GameResourceIntegrationTest.scala
+++ b/modules/core/src/test/scala/de/nowchess/chess/resource/GameResourceIntegrationTest.scala
@@ -1,11 +1,13 @@
 package de.nowchess.chess.resource
 
+import de.nowchess.api.board.Square
 import de.nowchess.api.dto.*
 import de.nowchess.api.game.GameContext
-import de.nowchess.chess.client.IoServiceClient
+import de.nowchess.chess.client.{IoServiceClient, RuleMoveRequest, RuleServiceClient, RuleSquareRequest}
 import de.nowchess.chess.exception.BadRequestException
 import de.nowchess.io.fen.FenExporter
 import de.nowchess.io.pgn.PgnParser
+import de.nowchess.rules.sets.DefaultRules
 import io.quarkus.test.InjectMock
 import io.quarkus.test.junit.QuarkusTest
 import jakarta.inject.Inject
@@ -14,6 +16,7 @@ import org.junit.jupiter.api.{BeforeEach, DisplayName, Test}
 import org.junit.jupiter.api.Assertions.*
 import org.mockito.ArgumentMatchers.any
 import org.mockito.Mockito.when
+import org.mockito.invocation.InvocationOnMock
 
 import scala.compiletime.uninitialized
 
@@ -29,6 +32,10 @@ class GameResourceIntegrationTest:
   @RestClient
   var ioClient: IoServiceClient = uninitialized
 
+  @InjectMock
+  @RestClient
+  var ruleClient: RuleServiceClient = uninitialized
+
   @BeforeEach
   def setupMocks(): Unit =
     when(ioClient.importFen(any())).thenReturn(GameContext.initial)
@@ -37,6 +44,32 @@ class GameResourceIntegrationTest:
     )
     when(ioClient.exportFen(any())).thenReturn(FenExporter.exportGameContext(GameContext.initial))
     when(ioClient.exportPgn(any())).thenReturn("1. e4 c5")
+    when(ruleClient.legalMoves(any())).thenAnswer((inv: InvocationOnMock) =>
+      val req = inv.getArgument[RuleSquareRequest](0)
+      DefaultRules.legalMoves(req.context)(Square.fromAlgebraic(req.square).get),
+    )
+    when(ruleClient.allLegalMoves(any())).thenAnswer((inv: InvocationOnMock) =>
+      DefaultRules.allLegalMoves(inv.getArgument[GameContext](0)),
+    )
+    when(ruleClient.applyMove(any())).thenAnswer((inv: InvocationOnMock) =>
+      val req = inv.getArgument[RuleMoveRequest](0)
+      DefaultRules.applyMove(req.context)(req.move),
+    )
+    when(ruleClient.isCheck(any())).thenAnswer((inv: InvocationOnMock) =>
+      DefaultRules.isCheck(inv.getArgument[GameContext](0)),
+    )
+    when(ruleClient.isCheckmate(any())).thenAnswer((inv: InvocationOnMock) =>
+      DefaultRules.isCheckmate(inv.getArgument[GameContext](0)),
+    )
+    when(ruleClient.isStalemate(any())).thenAnswer((inv: InvocationOnMock) =>
+      DefaultRules.isStalemate(inv.getArgument[GameContext](0)),
+    )
+    when(ruleClient.isInsufficientMaterial(any())).thenAnswer((inv: InvocationOnMock) =>
+      DefaultRules.isInsufficientMaterial(inv.getArgument[GameContext](0)),
+    )
+    when(ruleClient.isThreefoldRepetition(any())).thenAnswer((inv: InvocationOnMock) =>
+      DefaultRules.isThreefoldRepetition(inv.getArgument[GameContext](0)),
+    )
 
   @Test
   @DisplayName("createGame returns 201")
diff --git a/modules/rule/src/main/resources/application.yml b/modules/rule/src/main/resources/application.yml
index 2c5486b..98b81ce 100644
--- a/modules/rule/src/main/resources/application.yml
+++ b/modules/rule/src/main/resources/application.yml
@@ -1,5 +1,5 @@
 quarkus:
   http:
-    port: 8081
+    port: 8082
   application:
     name: rule-service
diff --git a/modules/rule/src/main/scala/de/nowchess/rules/sets/DefaultRules.scala b/modules/rule/src/main/scala/de/nowchess/rules/sets/DefaultRules.scala
index 036f00d..ed3bde2 100644
--- a/modules/rule/src/main/scala/de/nowchess/rules/sets/DefaultRules.scala
+++ b/modules/rule/src/main/scala/de/nowchess/rules/sets/DefaultRules.scala
@@ -3,7 +3,7 @@ package de.nowchess.rules.sets
 import de.nowchess.api.board.*
 import de.nowchess.api.game.GameContext
 import de.nowchess.api.move.{Move, MoveType, PromotionPiece}
-import de.nowchess.rules.RuleSet
+import de.nowchess.api.rules.RuleSet
 
 import scala.annotation.tailrec