Nagasaki is the capital of the Nagasaki Prefecture in Japan, and the city with the largest population in the Kyushu region. In August 1945, Nagasaki was subject to one of the two atomic bombs dropped by the United States during World War II.
In August 1945, First Lieutenant Ichirō Yashida was stationed at a POW internment camp in Nagasaki for American soldiers. An alarm was raised to alert the soldiers present of the imminent atomic detonation, and the Japanese forces decided to let the American soldiers escape from their prisons.
Yashida was tasked with unleashing their most infamous prisoner, the immortal Logan from a special armored cell deep underground. Private Yashida cut the chains surrounding the cell door and opened it, telling Logan to leave. Logan refused because he knew there'd be no outrunning it, and told Yashida to come down with him. Yashida was ordered by his superiors to return and commit seppuku to avoid facing defeat at the hands of their enemies.
As each of his fellow soldiers willingly committed the act, Yashida prepared to follow suit but was shocked by the sheer power of the nuclear detonation. Before he could bring himself to continue, Logan stopped him and ordered him to run to the cell for protection. Yashida jumped down and Logan shielded his body with the door of the cell, taking the full brunt of the atomic blast.
After the blast abated, Logan was horrifically burnt but began to heal from his injuries, to Yashida's bewilderment. Yashida tried to go to the surface, but Logan stopped him on account of the harmful amounts of radiation still present in the atmosphere. As a show of respect for Logan saving his life, Yashida willingly gave him his sword, Danzan to thank him.
Several hours later, Logan and Yashida realized it was time to head to the surface, climbing up the cell walls. When Yashida glanced upon the ruins of his city, he visibly wept.
In the year 2013, Logan returned to the site of the prison cell in Nagasaki where he and Yashida hid with his granddaughter Mariko.