Two players play on a board ruled into a grid of 5 ranks (rows) by 5 files (columns).
From largest to smallest (most to least powerful) they are: The names of the pieces combine their promoted and unpromoted values, and are puns in Japanese for words with the same pronunciations but different kanji.
Every time a piece makes a move it alternately promotes and reverts to its unpromoted state.
The original rules states that a third repetition would end the game as a draw, but kept open the possibility that this should be changed if playing experience would reveal it as undesirable.
An alternative would be to declare a loss for the player repeating a position too many times, except in cases of perpetual check, where the checker would lose.