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.

Kaiji shows everyone that Ōtsuki is cheating by using his special dice. He then tricks the foreman into betting again while Kaiji and his group use their own "special dice", with a 1 on each side, and thus Ōtsuki is forced to pay 5 times the amount they bet, losing 2,535,000 perica in total. Just when Ōtsuki was about to give up for the night, Kaiji reminds him that he still has to deal one more time according to the rules. The Forty-fivers then bet all 3,042,000 perica against the dealer.

Kurosaki intervenes and tells Ōtsuki that he has no choice but to play, and in the end, he loses 18,252,000 perica which Kaiji splits equally between the Forty-fivers. Kaiji then asks Kurosaki to approve their requests for the one-day outside pass and he agrees. The Forty-fivers insist that Kaiji should keep the money and twenty one-day outside passes, leaving him with ¥800,000 (around US$7,800) to gamble for the team and pay off their debts. Now back in society above ground, Kaiji meets Sakazaki Kōtarō who is looking for a partner to win big in the illegal casinos. Kaiji accepts his offer, and is taken to an illegal casino where he sees a huge Pachinko machine called "The Bog". Each ball is worth 1,000 times more than normal and the jackpot is worth ¥550 million, more than enough to free Kaiji from debt.

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.

Kaiji commences to play with the last ¥10 million he borrowed from Endō for a final assault, unaware that Ichijō has tilted the machine in the same direction that Kaiji's group tilted the building, thus creating an almost insurmountable tilt on the first two plates. When half of the money is gone, Ichijō gloats to Kaiji that he can never win, but Kaiji says that he knows about the tilt. As the crowd watches, Kaiji tapes three ¥10,000 bills to the glass, hiding the three plates. In frustration, Ichijō rips them off to see a number of balls circulating on the plates because the losing holes have become clogged with balls which are unable to exit the machine. This increases Kaiji's probability of winning, however they still do not drop into the winning hole.

Even with the plates filled to the brim with silver balls, Ichijō's secret weapon, the Curtain of Wind, prevents Kaiji from winning and Kaiji has run out of money. As he is dragged away, Sakazaki appears swearing vengeance on the machine, and gives Kaiji another ¥10 million which he again 'borrowed' from the company safe. Kaiji starts playing again with renewed vigor. The bottom plate is now awash with balls, but none can pass the curtain of wind around the winning hole. The machine appears to groan, and with the plate overflowing with balls, some cascade down the winning hole. Horrified that Kaiji won, Hyōdō sentences Ichijō to 1,050 years underground.

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.