Ignorami often refer to it as hari kiri or, even worse, harry carry <shudder>. Hara kiri (腹切) is more frequently called seppuku (切腹) in Japanese—the kanji are the same for both, but the order is reversed.
The Gaijin Gleaner from Kyushu brings us a wonderfully irreverent practical guide on how to commit ritual suicide à la mode japonaise.
One of the interesting things about seppuku is that, although it is an excrutiating way to die, once you’ve showed willing, as it were, by giving your guts a good digging with the knife, you are no longer required actually to hang around until you expire. At this point, your lieutenant, or kaishakunin, finishes you off with a sword blow to the neck:
Choosing an appropriate Kaishaku-nin is obviously very important. You should consider the following. Beheading being very infra dig points are deducted for actually detaching the head. Make sure your kaishakunin has practiced and perfected the “daki-kubi” cut so that your head is left attached to the body by a short flap of skin. This ensures your face is hidden, demonstrates his prowess with a sword and entirely remove the stigma of decapitation.