The story depicts the serious competition in the world of professional competitive mahjong between the "digital" school, which believes only in efficiency and probability, and the "occult" school, which believes in its own theories of unknown scientific basis, and the main character Natsuki, who belongs to neither of these groups.

This work is a relay manga in which different manga artists give their own interpretation to the theme in one page.

The newest edition of Mahjong Primer, featuring all Katayama characters, teaches beginners how to go to a mahjong parlor by themselves and play mahjong. Features visually pleasing cartoons and easy-to-understand explanations. (Source: Kodansha, translated)

Sadameda Souta, a college student who is considered the unluckiest man in Japan, as he constantly draws the worst hands and tiles in every game —Gaining him the nickname of "Million Shanten Man"—, meets and consequently challenges a new student for a game, getting beaten as always. This new student's name is Meronhadake Momomi, a busty woman who has the best luck in mahjong. After this encounter, Momomi and Souta hang out together, playing mahjong sometimes, meeting all types of people, then later getting involved in affairs pertaining to the competitive mahjong world.

Usukage Yuu is almost like a ghost, with most people not being able to feel his presence at all; Yuu takes advantage of this in order to win a title in a mahjong tournament. However, there is one individual who is able to win against Yuu: a mysterious newcomer by the name of Tsukimi Shiruru. Now, as Yuu finds someone who can win against him, he begins to study under Shiruru's guidance. What is more important to win? Precise tactics or probability theory?

The story of a florist and a young girl he takes in after the death of her parents.