Magic File 3: Shinichi and Ran, Memories of Mahjong Tiles and Tanabata

Story
This starts off with Conan, Kogoro Mouri and three other friends playing mahjong. Kogoro mistakes a white tile with a grape peel to be a 1-pin and looses the game. Conan tells it to the detective boys and the professor and Conan and Agasa explains what white and 1-pin is. The next day, the four friends plus Conan and Ran meet and play some mahjong. Kouda is teased by Okano about his wife and Kouda later gets mad at that. Ran starts to go into a flash-back about when she and Shinichi were in first grade and went to a Tanabata festival.

Resolution
This leads into the 13 movie: The Raven Chaser, which has a case concerning mahjong pi.