They understood things of the spirit in Japan.
They disemboweled themselves when anything went wrong.
I tried to imagine how they would go about it. They must have an extremely sharp knife. No, probably two extremely sharp knives. Then they would sit down, cross-legged, a knife in each hand. Then they would cross their hands and point a knife at each side of their stomach. They would have to be naked, or the knife would get stuck in their clothes.
Then in one quick flash, before they had time to think twice, they would jab the knives in and zip them round, one on the upper crescent and one on the lower crescent, making a full circle. Then their stomach skin would come loose, like a plate, and their insides would fall out, and they would die.
It must take a lot of courage to die like that.
- Sylvia Plath, The Bell Jar
If I remember correctly, it is not a quick flash. The person committing harakiri is meant to feel of the process as much as possible. There’s even that movie where the ronin is made to do it with a wooden sword.