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:
All other rules are as in Grand chess.