Kaiji agrees to play Chinchirorin with the other workers and foreman Otsuki. Kaiji spends several rounds making small wagers to get a feel for the game. Dissatisfied with the small payout, Kaiji bets big- 3,000 Perica against the timid man Miyoshi.

Kaiji loses his first bet of 3,000 Perica, but strengthens his resolve to fight. He continues to make bets of 3,000 Perica. After 40 minutes of gambling, he ups the ante and bets 5,000 Perica against foreman Otsuki and his lackey. They respond with enormous bets- each betting the house limit of 20,000 Perica.

Weeks have passed since Kaiji's crushing loss on gambling night, and he finds himself in a cycle of debt with a group of five others, including Miyoshi. The group is referred to by the other workers as the "45s". With the help of Miyoshi, Kaiji discovers that the foreman's group is cheating. Kaiji rallies the 45s together to come up with a plan.

While Kaiji is on medical duty, he meets the son of Ishida, Hiromitsu, who is also working underground for his debt, but blames his father for not bailing him out. Angrily Kaiji berates him for not accepting his own weaknesses. Later, Kaiji insults Ōtsuki who then makes life a misery for Kaiji and the Forty-fivers, but after three months they all return to full pay. Meanwhile, Kurosaki Yoshihiro, Tonegawa's replacement, observes Kaiji through CCTV. When the gambling night begins, Kaiji proposes no betting limit before he will join in and Ōtsuki accepts.

Kaiji and Ōtsuki prepare to face each other over cee-lo, each thinking they have an edge. For the first few matches, Kaiji does not bet over the old limit of 20,000 perica and everyone gets bored with Kaiji betting so little. On a challenge from Ōtsuki who must deal twice, Kaiji bets his entire 52,000 perica and signals the Forty-fivers who each bet 92,000 perica, for a total of 507,000 perica.

Kaiji plays on even though it appears the chances of winning are zero. Meanwhile, Ichijō receives a request to send a live CCTV feed to the Teiai underground forced labor camp and to Hyōdō. Kaiji continues to play, even after losing ¥20 million in what seems a pointless exercise.

Kaiji has only ¥20 million left to try and beat the Bog, however he is confident as he is aware of how the three bottom plates are rigged. He explained this to Sakazaki when they were at the racetrack. Slowly Ichijō comes to realize that Kaiji managed to not only tilt the machine to increase his odds of winning, but also create a slightly favorable tilt on the casino building. Unbeknownst to him, Kaiji's group had poured 20 tons of water into plastic tanks in a room on one side of the casino building, causing it to subside slightly on that side.

Kaiji plays on, but he is on the verge of defeat, having lost all his money. He convinces Endō to lend him his last ¥10 million against his better judgement, but at an exorbitant interest rate, and Kaiji returns to the machine for a final assault.

As Ichijō is removed by the men in black, Kaiji tells him to fight his way back to the surface for a rematch. Meanwhile, Kaiji's friends cash in the balls he won for a total of over ¥729 million. Kaiji, Sakazaki and Endō settle their debts and split the remainder for almost ¥190 million each, from which Kaiji must pay back his friends in the underground labor camp.