diff --git a/nakama/go-modules/main.go b/nakama/go-modules/main.go
index af4365b..7fab08a 100644
--- a/nakama/go-modules/main.go
+++ b/nakama/go-modules/main.go
@@ -700,6 +700,20 @@ func (m *ChessMatch) MatchLeave(ctx context.Context, logger runtime.Logger, db *
 				})
 				dispatcher.BroadcastMessage(OpCodeGameOver, msg, nil, nil, true)
 
+				// Update match label to finished so it's not detected as active
+				label := MatchLabel{
+					Game:       "chess960",
+					Status:     "finished",
+					Result:     s.Result,
+					White:      s.WhiteName,
+					WhiteID:    s.WhiteID,
+					Black:      s.BlackName,
+					BlackID:    s.BlackID,
+					PositionID: s.PositionID,
+				}
+				labelJSON, _ := json.Marshal(label)
+				dispatcher.MatchLabelUpdate(string(labelJSON))
+
 				logger.Info("Game forfeited: %s", s.Result)
 			}
 		}
@@ -753,14 +767,77 @@ type MoveResult struct {
 	Reason  string
 }
 
+// Convert Chess960 FEN castling notation to standard notation for chess library compatibility
+func convertChess960FenForLibrary(fenStr string) string {
+	parts := strings.Split(fenStr, " ")
+	if len(parts) < 3 {
+		return fenStr
+	}
+
+	castling := parts[2]
+	// Check if it's already standard notation or empty
+	if castling == "-" || castling == "KQkq" || castling == "KQ" || castling == "kq" ||
+	   castling == "K" || castling == "Q" || castling == "k" || castling == "q" ||
+	   castling == "Kq" || castling == "Qk" || castling == "Kk" || castling == "Qq" {
+		return fenStr
+	}
+
+	// Convert Chess960 file-based notation (like HBhb) to standard KQkq
+	newCastling := ""
+	hasWhiteKingside := false
+	hasWhiteQueenside := false
+	hasBlackKingside := false
+	hasBlackQueenside := false
+
+	for _, c := range castling {
+		if c >= 'A' && c <= 'H' {
+			// White castling - higher file = kingside, lower = queenside
+			if c >= 'E' {
+				hasWhiteKingside = true
+			} else {
+				hasWhiteQueenside = true
+			}
+		} else if c >= 'a' && c <= 'h' {
+			// Black castling
+			if c >= 'e' {
+				hasBlackKingside = true
+			} else {
+				hasBlackQueenside = true
+			}
+		}
+	}
+
+	if hasWhiteKingside {
+		newCastling += "K"
+	}
+	if hasWhiteQueenside {
+		newCastling += "Q"
+	}
+	if hasBlackKingside {
+		newCastling += "k"
+	}
+	if hasBlackQueenside {
+		newCastling += "q"
+	}
+
+	if newCastling == "" {
+		newCastling = "-"
+	}
+
+	parts[2] = newCastling
+	return strings.Join(parts, " ")
+}
+
 // Validate chess move using corentings/chess/v2 library
 func validateChessMove(fenStr, from, to, promotion string, logger runtime.Logger) MoveResult {
 	result := MoveResult{Turn: "w"}
 
-	logger.Info("validateChessMove: FEN=%s, move=%s%s", fenStr, from, to)
+	// Convert Chess960 castling notation to standard for library compatibility
+	convertedFen := convertChess960FenForLibrary(fenStr)
+	logger.Info("validateChessMove: original FEN=%s, converted=%s, move=%s%s", fenStr, convertedFen, from, to)
 
 	// Parse FEN
-	fen, err := chess.FEN(fenStr)
+	fen, err := chess.FEN(convertedFen)
 	if err != nil {
 		logger.Error("validateChessMove: FEN parse error: %v", err)
 		return result