Grandhouse is a custom variant combining the rules of Grand chess with the drop rules of Crazyhouse. The same rules apply to both games. As this is considered a derivative of Grand chess, please check the Grand chess rules in its separate guide. Crazyhouse rules are as below for a reminder.
Given the larger board size, the rules are slightly different for the last three ranks. Pawns cannot be dropped in the last three ranks.
Drops can be performed with captured pieces, which would be done in lieu of moving a piece on the board. Drops are annotated with @. So for example, R@e4 means rook drop at e4. The rules for dropping pieces are as follows:
- Drops resulting in immediate checkmate are permitted. Unlike in shogi, this includes pawn drops.
- Pawns may not be dropped on the players' 1st or 8th - 10th ranks.
- Pawns that have been promoted and later captured are dropped as pawns.
- Dropped white and black pawns on the 3rd and 8th ranks, respectively, are permitted to make a two-square move as their first move after the drop.
All other rules are as in Grand chess.
As in standard crazyhouse, the piece values don't align with the chess piece values, and as in standard crazyhouse, sacrificing material for fast development, attacks on the enemy King, or just for defence, are often wise. Sometimes it is better to reinforce defenders around one's King rather than try to save them. Here we may refer you to sources in standard crazyhouse strategy…