Better known as hara-kiri (although this term was considered vulgar by the samurai) Seppuku was a form of suicide reserved solely for the samurai because it took such a vast amount of courage to go through with it. The samurai to be killed would usually be dressed in a white kimono, and would kneel on a pillow. A close friend chosen as his second would stand about a meter to the left. (His task was to cut off the samurai's head as soon as he showed significant pain.) The samurai would then expose his abdomen (where the spirit was believed to reside), unsheath a knife laid before him, and begin an incission through his stomach that moved from left to right. The blade was then turned in the wound and brought upward. To complete the entire ceremony was considered a great honor, but usually the second would decapitate him before he finished, as it was indescribably painful throughout.
There were three types of Seppuku:
Junshi was suicide after the death of one's lord. This was eventually outlawed as wasteful.
Kanshi was a rare form where one killed oneself to make a point to a lord when all other forms of persuasion failed.
Sokotsu-shi was the most common form, and consisted of commiting suicide to make ammends for a transgression. This could include striking another with a sword out of anger which was often punished by obligated suicide. In another case, an unfortunate samurai was compelled to kill himself by law for harming a dog during the later samurai period.