Ten years ago, they took him in. He doesn't even know who. And for ten years, he has been confined in a private prison. He doesn't know why. For ten years, his only contact with the outside world has been a television set and the voices of his jail mates. In time, he lost himself. He changed...transformed himself into something else...something hard...something lethal. Suddenly, one day his incarceration ends, again without explanation. He is sedated, stuffed inside a trunk, and dumped in a park. When he awakes, he is free to reclaim what's left of his life...and what's left is revenge. (Source: Dark Horse) Includes an epilogue in the final volume.

Okimoto Shun dropped out of college to become a professional mahjong player. He plays in the mahjong parlors of Shinjuku, where he encounters many formidable opponents. When the story kicks off, his primary mahjong parlor has just gone out of business, and he is looking for somewhere else to play. In the mahjong parlors of Shinjuku, Shun will play many games of mahjong with many different people, improving his game through experience!

Mahjong.

A homeless unemployed man gets by thanks to his mahjong skills. He's a talented player & one day he's asked to participate in a game with rates 10 times higher than usual. (Manga Mogura)