Touhou Kaikidan ~ Mystic Square (東方怪綺談 ～ Mystic Square) is the fifth official installment of the Touhou Project series and is a 2D vertically-scrolling danmaku shooting game (shoot em up). It is the last game in the Touhou Project series for the Japanese PC-98. It is also the last game to have ever been officially released for the PC-98, released on December 30th, 1998. In this game, the playable character (Reimu, Marisa, Mima or Yuuka) travels to Makai after a horde of demons came out of a cave in order to confront Shinki about that problem in particular.

KirbyComment makes their way through the game on Lunatic difficulty as Mima, notably not dropping any point item as well as grazing and milking a lot of patterns and attains a score of 284,581,040 points. Please read the author's comments for more details. For reference, the best known real time score is 202,717,620 points by Miller.

This is the first ever publication of a game made for the PC-98 series of computers, which were only released in Japan.