  Shogi is a traditional Japanese strategy board game in the same family as
chess, chaturanga, and xiangqi, and has been theoretically studied from various
aspects. The research on recommended sequences of moves in each opening of
shogi is called joseki; how to use a rook (Static Rook and Ranging Rook), or
how to develop a castle, etc. Also, many pieces of tsume shogi, artistic shogi
miniature problems, in which the opponent's king is checkmated by a series of
checks, have been created involving various beautiful techniques such as "saw"
and "puzzle ring". In addition, the rapid development of AI in recent years has
led to the pursuit of the best possible moves in shogi. In this paper, we move
away from the study of winning and losing in shogi and focus on the
mathematical aspects of the movement of shogi pieces. We propose to correspond
movements of shogi pieces to a set of geometrical patterns constructed by the
shape of shogi pieces and representing the Frieze group through the condition
regarding the neighborhood of arrangements of given shogi pieces. Although the
discovery of this correspondence does not lead to a winning strategy for shogi,
however, it does demonstrate a curious involvement between the traditional
Japanese board game and Western mathematics.
