Tobaku Mokushiroku Kaiji
He was saved from death on a whim by Kaiji on the Espoir after he was tricked by Sakai by paying for his release from the back room.
He is later seen participating in another gambling tournament, the Human Derby. Despite admiring Kaiji, Kaiji avoids him seeing that it is a competition.
In the first leg of the race, Ishida managed to accomplish second place, earning a certificate redeemable for ¥10 million.
During the second part of the race, while overcome by immense fear, Ishida recognized that he was not a man born to be a success in this world, and entrusted his certificate to Kaiji, who he felt had the skill, power and confidence to survive. He urges Kaiji to go forward and not look back, and while Kaiji is concentrating on maintaining his balance, Ishida falls off from the steel bridge, covering his mouth so Kaiji would not hear his screams as he descends.
Tobaku Hakairoku Kaiji
Kaiji encounters his son, Hiromitsu Ishida, at the underground labor camp. His son explains that after his father returned from the Espoir he would tell him his about his savior, Kaiji.
After Kaiji defeats the Bog, with the remaining money he pays off the debt of Hiromitsu, fulfilling the promise he made to Ishida.