Mini-Shogi is a version of modern Japanese Chess shrunk to a much smaller (5x5) board. Apart from the reduced board size and number of pieces, the rules are exactly the same as those of normal Shogi, except for one: A 4-fold repetition that is not a perpetual check is not a draw, but a loss for sente. A short summary of those rules:

S, B and R can optionally promote when they reach the last rank, or start their move there. For P such promotion is mandatory. When captured, pieces revert to the unpromoted form. Captured pieces change side, and can be dropped from the hand on any empty square. Except that P cannot be dropped on the last rank, and that it is not allowed to checkmate the opponent with a Pawn drop. Pieces dropped in the zone do not yet promote on the drop, but must move first. Perpetual checking is forbidden.

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