Crazyhouse is a variation of chess where captured opponent's pieces change color and can be returned to the board by you as your own pieces. On your turn, instead of a normal move, you can place any piece from the reserve on any empty square of the board (except pawns on the first and eighth ranks). All other rules of classic chess remain unchanged, including castling, en passant capture, and the rules for promoting pawns.
To play online with real players, as well as online bots, go to the "tables" tab, select a table that suits your parameters and join the game. You can also create your own gaming table with the desired settings by clicking the "create game" button. In training mode, you can play offline with yourself or with the computer. The more time you give the artificial intelligence to think, the better it will play. In addition, if the game is new to you and you want to understand what strategy and tactics to follow, you can choose a CPU vs. CPU game and watch the process.