Whale Shogi is a variant of Shogi, Japanese chess. However, unlike most other Shogi-variants, Whale Shogi roots are not in Japan, but in the U.S., and the game also is mostly played outside Japan (although it is not clear how often). It was invented in 1981 by R. Wayne Schmittberger (the author of New Rules for Classis Games; however, he does not mention Whale Shogi in this book). As is more common in shogi variants, the inventor has named all pieces after a kind of animal: in this case all are whales and related animals.
The game is played on a 6 by 6 board. Each player has twelve pieces: one white whale (who fulfils the role as `king'), one humpback, one grey whale, one porpoise, one narwhal, one blue whale, and six dolphins. Additionally, there is the killer whale: a piece that comes only into play by taking the opponents porpoise. The opening setup is as follows:
White whale c1; Porpoise d1; Humpback a1; Grey Whale b1; Narwhal e1; Blue Whale f1; Dolphin a2, b2, c2, d2, e2, f2.
White whale d6; Porpoise c6; Humpback f6; Grey Whale e6; Narwhal b6; Blue Whale a6; Dolphin a5, b5, c5, d5, e5, f5.
The white whale moves as a king, i.e., one square in an arbitrary direction.
The porpoise moves one square to the left or to the right, so the porpoise cannot leave the first rank.
The humpback moves one square diagonally or one square straight backwards. (This is precisely the reversed of the moves of the silver general from Shogi.)
The grey whale moves straight forward as a rook, and diagonally backwards as a bishop. (So, it moves like a queen but only in three of the possible eight directions.)
The narwhal moves either one square to the left, one square to the right, one square straight backwards, or exactly two squares straight forwards. In the latter case, the narwhal may jump over a possible piece.
The blue whale moves one square straight or diagonally forwards, or one square straight backwards. (So, it can move in four different directions.)
The dolphin moves one square straight forward. (As all other pieces in this game, dolphins take in the same way as they move, thus differing from the chess-pawns.) When a dolphin is on the last rank of the board at the opponents side, it may make one move as a bishop: after that, he moves again only one square forward, until he reaches again the last rank.
Finally, there is the extra piece, the killer whale, which comes into play after taking a porpoise of the opponent (see below). It has the combined moves of king and rook, i.e., it moves horizontally or vertically an arbitrary number of unobstructed squares like a rook, or one square diagonally.
As in Shogi, pieces taken from the opponent can be used as reinforcements: instead of making a normal move, a player can put one of the pieces he took earlier in the game from the opponent, and put this piece on an empty square; it is now one of his own pieces.
There are two special rules about drops. When a player has taken the enemies porpoise, he does not get the porpoise to drop, but instead a killer whale. (Note the big difference in strength between the two pieces.) One may not drop a dolphin on the last row (at the enemies side of the board), to give checkmate, or on a column that contains already two or more dolphins of the player.
The player that takes the white whale of the opponent wins the game. It is disallowed to give perpetual check.