diff --git a/src/ui/flutter/lib/board/board_widget.dart b/src/ui/flutter/lib/board/board_widget.dart
index a7195c99..71f11e5e 100644
--- a/src/ui/flutter/lib/board/board_widget.dart
+++ b/src/ui/flutter/lib/board/board_widget.dart
@@ -61,9 +61,9 @@ class BoardWidget extends StatelessWidget {
         final row = (dy - padding - digitsHeight) ~/ squareWidth;
         final column = (dx - padding) ~/ squareWidth;
 
-        final index = row * 6 + column;
+        final index = row * 7 + column;
 
-        print("Tap on ($row, $column) => $index\n");
+        print("Tap on ($row, $column) <$index>");
 
         if (row < 0 || row > 6) return;
 
diff --git a/src/ui/flutter/lib/mill/position.dart b/src/ui/flutter/lib/mill/position.dart
index 2fd05a0c..c114fd78 100644
--- a/src/ui/flutter/lib/mill/position.dart
+++ b/src/ui/flutter/lib/mill/position.dart
@@ -53,7 +53,7 @@ class Position {
     }
 
     // Debugging
-    _board[sqToLoc[8]] = Piece.whiteStone;
+    _board[sqToLoc[8]] = Piece.blackStone;
     //_board[7] = Piece.ban;
     //_board[8] = Piece.whiteStone;
 
diff --git a/src/ui/flutter/lib/routes/battle_page.dart b/src/ui/flutter/lib/routes/battle_page.dart
index 72ea3f8b..380422a6 100644
--- a/src/ui/flutter/lib/routes/battle_page.dart
+++ b/src/ui/flutter/lib/routes/battle_page.dart
@@ -46,13 +46,14 @@ class _BattlePageState extends State<BattlePage> {
     final position = Battle.shared.position;
 
     // 仅 Position 中的 side 指示一方能动棋
-    if (position.side != Side.white) return;
+    if (position.side != Side.black) return;
 
     final tapedPiece = position.pieceAt(index);
+    print("Tap piece $tapedPiece at <$index>");
 
     // 之前已经有棋子被选中了
     if (Battle.shared.focusIndex != Move.invalidIndex &&
-        Side.of(position.pieceAt(Battle.shared.focusIndex)) == Side.white) {
+        Side.of(position.pieceAt(Battle.shared.focusIndex)) == Side.black) {
       //
       // 当前点击的棋子和之前已经选择的是同一个位置
       if (Battle.shared.focusIndex == index) return;