A direct sequel to Tobaku Datenroku Kaiji, picking up immediately after Part 3 ends. After his tremendous victory in 2-Player Mahjong against the villainous President, Muraoka Takashi, Kaiji is being driven home by Kazuya, the son of Chairman Hyoudou. However, in the car, Kazuya asks Kaiji if he would be interested in one more gamble that night, and Kaiji accepts. What surprises lie in store for our dear Kaiji, and what will the gamble be?!

Itou Kaiji, now free of debt but without a penny is leeching himself in Mr.Sakazaki's new house, despite all the flirtings (extreme torment for Kaiji) from Sakazaki's daughter, Mikoko. Sakazaki attempts to kick Kaiji out, even by offering a farewell 'we never knew each other' money of 3000000 yen. While Kaiji ponders himself on the decision, he is visited by Miyoshi and Maeda, two of his 'allies' he had saved from the last part of the series.

Kaiji and Kazuya face off against each other in a high-stakes game of "One Poker," a modified version of standard poker. Kazuya sets forth a gamble of 2,000,000,000 yen! How will Kaiji survive?! <br><br>
<i>Chapter count for this arc is 101-254 in the original tankoubon.</i>

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