Crazyhouse is a chess variant where all the rules and conventions of standard chess apply, with the addition of drops, this means that a captured piece reverses color and goes to the capturing player’s reserve or pocket. At any time, instead of making a move with a piece on the board, a player can drop a piece from his reserve onto an empty square on the board.
This game is extremely tactical with a huge emphasis placed on initiative where an extra tempo or two can lead to a crushing attack, finishing the game soon with checkmate. Even a small weakness like a square around the king and only protected by him, could lead to receive a checkmate if opponent has a handful of pieces in reserve to drop with continuous checks.
Strategic Crazyhouse aims to make Crazyhouse more similar to Chess, this means making a much more strategic game, much better balanced between attack and defense. This is accomplished by adding three rules governing how the drops are made:
- Rule 1A drop move with a check is illegal
- Rule 2Pawns can only be dropped from second rank to sixth rank
- Rule 3Pieces can only be dropped from first rank to seventh rank
Some time ago, Stockfish, one of the strongest programs in Chess and currently with a rating of 3390, was modified by several enthusiastic programmers of the Lichess community to play Crazyhouse, so taking advantage of this opportunity to start from an excellent base, I could modify this program so that it can also play Strategic Crazyhouse.
The result is awesome, similarly to how Stockfish easily defeated all the current Crazyhouse programs, in this new variant of Strategic Crazyhouse the result was the same, and it completely defeated Sjeng and Sunsetter.
Here are some games showing how Stockfish defeats Sunsetter which is already far better than Sjeng:
And here are some blitz games played by me vs Sjeng, a chess and variants playing program which its Crazyhouse rating fluctuates around 2300 points:
You can download everything you need to play this variant, let Stockfish analyze positions or even, if you are a programmer, you also have the source code available: