Historical clue formulations

• Japanese game using pentagonal pieces — 2024-11-30
• Board game popular in Japan — 2023-05-28
• Japanese chess — 2017-06-22
• So-called Japanese chess — 2015-02-27
• Japanese chess — 2014-01-07
• Japanese chess — 2010-02-11
• Game played on an 81-square board — 2008-12-20