We watched an episode of an old Japanese detective TV show, about a murder that happened during a Shogi match. It’s a clever setup because we get to see a little bit the world of Shogi players, and the solution requires some knowledge about Shogi. Why did one of the grandmasters play a fatally flawed move at the critical moment of the match? The detective reasoned that it’s because he didn’t want to turn his piece over, which would revealed a trace of blood on the backside. I had toook this up. In Shogi, after a piece is promoted, you turn it over. The characters written on the other side indicate the new role of the piece.