In the world of Shogi (Japanese Chess), there are professional players who make their living at the game and gamblers who play Shogi for money. In Hachi-One Diver, gamers take the latter tack and play Shogi against an assortment of opponents who vary in their level of skill and attitude.

Based on the manga by Shibata Yokusaru which was made into an 11-episode television series, Hachi-One Diver on the PS2 features a Story Mode where players take on the role of Sugata Kentarou who possesses a decidedly blank visage. Sugata was once a promising student at the Shogi Player Foundation but he faltered and failed at his dream. Nowadays, he has taken the role of a Shogi gambler who earns his keep by facing opponents in Shogi parlors and contests. But he is devastated when he is beaten completely by a young woman known as "Ukeshi" who takes any challenges and never loses. As Shogi means everything to him, he decides to train himself harder to become the strongest player.

The Story Mode of the game follows Sugata's trials as he plays Shogi against a steady parade of competitors. By beating certain opponents, Sugata faces new challengers based on his performance. Hachi-One Diver also features a Versus Mode, a 2-Player Mode, and a Shogi School Mode that teaches newbies the basics of the game.