@jrandom42: Tsukihiko says he is 4 years old. This chapter takes place somewhere between June and November 1931. That means Tsukihiko is born somewhere between June 1926 and November 1927. So it's possible that he was not even 18 when the war ended in August 1945.
At the very least, we can safely say he did NOT take part in the Nanjing Massacre of 1937, thank fuck.