We will have to add additional opportunities for human on-line play (pychess.org, gamerz.net, freechess.org, chess.com), and for 'strong' computer opponents (Fairy-Stockfish, ChessV, Sjaak II, Nebiyu, HaChu, CrazyWa, KingSlayer...).
Since some of these engines are configurable, it would often be possible to supply game files for them, to use them for variants that are not in their standard repertoir.
Standard repertoir of Sjaak II:
Normal chess (Jazz, Sjaak and Leonidas all play this).
Spartan chess, where black and white play with different armies and black has two kings (Sjaak and Leonidas can both play this).
Seirawan chess, where both sides start with an extra off-the-board piece that can be introduced later (Sjaak and Leonidas both play this).
The Maharaja and the Sepoys, where white has only one piece (the Maharaja) (needs to be played as variant "fairy" in XBoard). In Sjaak II you need to load the variants.txt configuration file to make this variant available.
Amazon chess, where the queen moves as an amazon (needs to be played as variant "fairy" in XBoard).
Knightmate, where the king moves as a knight and the knights move as a king.
Berolina Chess, where pawns move one square diagonal and capture straight ahead.
Capablanca Chess, a variant played on a 10x8 board with two extra pieces.
Gothic Chess, the same as Capablanca Chess but with a different starting position.
Fischer Random Chess and Capablanca Random Chess, which are like normal chess and normal Capablanca chess, but with a randomised starting position (Sjaak does not generate a starting position, however).
Courier chess, a medieval variant played on a 12x8 board.
Chinese chess (Xiangqi), Black and white face eachother across the river that runs along the board, with their kings confined to their palaces.
Japanese chess (Shogi), where captured pieces can be dropped on the board to reinforce your own army. Also supported are a number of Shogi variants (sho-shogi, mini-shogi and tori-shogi).
Omega Chess, a variant on a 12x12 (effectively 10x10 with four extra squares) board.
Grande Acedrex, a large (12x12) mediaeval variant of chess with divergent pieces: the Rhinoceros/Unicorn (first as Knight, then as Bishop) and the Gryphon/Aanca (first as Ferz, then as Rook). Can be played by Postduif.
We will have to add additional opportunities for human on-line play (pychess.org, gamerz.net, freechess.org, chess.com), and for 'strong' computer opponents (Fairy-Stockfish, ChessV, Sjaak II, Nebiyu, HaChu, CrazyWa, KingSlayer...).
Since some of these engines are configurable, it would often be possible to supply game files for them, to use them for variants that are not in their standard repertoir.
Standard repertoir of Sjaak II: