Kerr Chess mostly follows traditional chess, including checkmate, castling, and en passant. The key differences:
Controls
Tap a piece, then a highlighted square to move. Pinch to zoom. Drag sideways to rotate, or up/down to tilt in 3D.
Click a piece, then a highlighted square to move. Scroll to zoom. Drag sideways to rotate, or up/down to tilt in 3D.
Keyboard: hold + / − to zoom, Q / E to rotate; 0 resets the view. On the board, use arrow keys and Enter to select and move.
Open View controls in the board’s bottom-right corner for camera buttons and Whole board to reset the view.