Hara-kiri (belly – cut) is a spoken term used by commoners to describe ritual suicide. Seppuku is the written form used amongst higher classes for the same act.
Part of the samurai bushido honor code, seppuku was committed either voluntarily by samurai who preferred to die with honor rather than surrender to their enemies or as capital punishment for samurai who had been shamed or committed serious offenses.
Although Seppuku as judicial punishment was abolished in 1873, many others, encouraged by militaristic propaganda, have subsequently carried it out. This was a common practice among soldiers and civilians choosing death rather than surrender in WWII.