Ōtsuki (大槻) is the foreman of Squad E in the underground labor camp. While he initially appears to be kind and helpful, in reality, he is just setting Kaiji up for an even greater fall.

He is the mastermind behind the dice game Underground Chinchiro and is the main antagonists in the first part of the Tobaku Hakairoku Kaiji arc.

He has a spin-off manga called Ichinichi Gaishutsuroku Hanchou were he is the main protagonist.


He is the foreman of Squad E along with his lackeys Isawa and Numakawa.

Tobaku Hakairoku Kaiji

Though he was initially friendly to Kaiji this was a ruse to encourage Kaiji to spend his all money buying food and alcohol from Ōtsuki. Ōtsuki then loans Kaiji some money to play Chinchirorin, then wins this money back from him, and forces him to work for half-pay to repay his debt.

After Kaiji figures out that Ōtsuki is cheating by using 4-5-6 dice (dice without the numbers 1, 2, or 3 on them) he exposes Ōtsuki in front of everyone with the help of the foreman from Squad C, Odagiri. Ōtsuki then agrees to let Kaiji and the other 45ers use rigged dice against him thinking he will only have to pay 2 or 3 times the amount bet, however Kaiji and the 45ers uses rigged dice that only roll 1 so Ōtsuki has to pay 5 times the amount bet (under Ōtsuki's rules if the 3 dice all show 1 the player wins 5 times their bet). After being dealer for 2 rounds Ōtsuki loses over 18 million perica and succumbs to complete defeat and humiliation.

He is later seen watching Kaiji challenge the Bog from the underground labor camp live feed of the event setup by Hyōdō. Still holding a grudge from what Kaiji had done to him, he hoped that Kaiji would lose at it.

Chūkan Kanriroku Tonegawa

He makes an appearance in the anime adaptation of Chūkan Kanriroku Tonegawa with the adaptation of first few chapters of his spin-off manga, Ichinichi Gaishutsuroku Hanchou.

He would later encounter Tonegawa in a restaurant not knowing the position each held in Teiai nor knowing that they were part of the same organization. Due to this, Ōtsuki manages to talk to Tonegawa normally without holding any fear despite Tonegawa having a severely higher position than him.


Chūkan Kanriroku Tonegawa

Ichinichi Gaishutsuroku Hanchou

Live Action Adaptation


  • In the main series, his surname is never revealed.
  • The crossover between Chūkan Kanriroku Tonegawa and Ichinichi Gaishutsuroku Hanchou in the manga was named "Tonegawa vs Hanchou" in Volume 5 of Chūkan Kanriroku Tonegawa.