Shogi descends from the same ancient Indian ancestor as chess but took a distinctive turn: pieces you capture become yours and can be parachuted back onto the board. That single rule makes draws almost unheard of and the endgame ferociously sharp.
Variant implemented
Standard modern Shogi (hon shōgi): 9×9, 20 pieces each, promotion in the last three ranks, captured pieces are dropped back into play with the standard drop restrictions.
Board and pieces
9×9, 81 squares. Twenty pieces each.
Setup
Back rank from the left: lance, knight, silver, gold, king, gold, silver, knight, lance. Second rank: bishop and rook on the two files shown in the standard diagram. Third rank: nine pawns.
Turn
Move a piece, or drop a piece from your hand onto any empty square.
Capture and scoring
Capturing takes the piece into your hand, where it becomes yours and can be dropped back into play later, unpromoted.
Win condition
Checkmate the enemy king. Stalemate — having no legal move — is also a loss.
Draw condition
Fourfold repetition (sennichite) is scored as a draw here.
Special rules
Promotion is available when a move starts or ends in the last three ranks, and is compulsory for a piece that would otherwise have no legal move. Drop restrictions: no two unpromoted pawns on the same file (nifu); no pawn or lance on the last rank; no knight on the last two ranks; and a pawn drop may not deliver immediate checkmate (uchifuzume).
Computer opponent
Alpha-beta with most-valuable-capture ordering and a depth cap suited to the branching factor. The evaluation combines material (including pieces in hand), mobility, king safety from nearby generals, and pawn advancement.