What is Hollow Chess?
Hollow Chess is a free chess variant where the board itself is a piece you can move. It plays by standard chess rules — same pieces, same moves, win by checkmate — with one addition: every third turn is a board turn. On a board turn you may move a piece as normal, or pick up an empty square and reattach it anywhere along the edge of the board.
The square you lift leaves a hole, and holes block sliding pieces. A bishop cannot see through one. Neither can a rook or a queen. So you can defend by deleting the ground an attack travels over, and escape check by reshaping the board instead of moving your king.
How is it different from normal chess?
- The board is not fixed. It grows, shrinks and changes shape as you play.
- Holes block lines. Bishops, rooks and queens cannot slide across a hole. Knights jump them.
- Promotion moves. Pawns promote at the edge of the world — extend the board and they must march further.
- Check has a second escape. On a board turn you can cut the attacker’s line rather than run.
Ways to play
- Against bots — a ladder of opponents from beginner to brutal, no account needed.
- Ranked online — matched against a player near your rating.
- With a friend by link — send one link and play live in the browser.
- Two players, one screen — offline hotseat.
- Correspondence — trade links a move at a time.
Hollow Chess is free, runs in any browser on desktop or mobile, and needs no download and no sign-up. It installs as an app if you want it to.