- Mitsuru Sasaki (1 August 1943 – 15 October 1955) was a Japanese boy who died of leukemia at the age of 12, about nine years after the atomic bombing of Hiroshima. He is commonly known by the nickname "Papa" (derived from "paper" in Japanese), which he was given by the hospital and nurses because he would constantly fold origami.
Masaru Sasaki
- Masaru Sasaki (5 January 1943 – 7 May 1956) was the older brother of Sadako Sasaki and the younger brother of Mitsuru Sasaki, both of whom died of radiation-related illnesses after the atomic bombing of Hiroshima. He was born in Hiroshima and was two years old at the time of the bombing. He attended Motomachi Elementary School with his sister, Sadako, and survived the initial blast. However, he later developed leukemia and died on 7 May 1956, at the age of 13.