On the upward stroke, the kaishakunin would perform daki-kubi. There were instances when the head flew off, so it was best for the daki-kubi to leave a little band of skin remaining so the head did not fly off toward the verifying officials. Because of the precision necessary for such a cut, the kaishakunin was often a skilled swordsman. If a defeated warrior had fought honorably and well, an opponent who wanted to salute his bravery would volunteer to act as his kaishakunin.

Some samurai chose to perform a form of seppuku known as jūmonji-giri "cross-shaped cut" in which there is no kaishakunin to provide a quick end to the samurai's suffering. It involves a second and more painful vertical cut across the belly and the samurai was expected to bear his suffering quietly while bleeding to death.

Seppuku has also been used as capital punishment for disgraced samurais, especially for those who had committed serious offenses such as murder, robbery, corruption, or treason. The samurai was given a set time to commit seppuku, usually before sunset on a given day. If the samurai was uncooperative, he would be restrained and forcibly decapitated. Unlike voluntary seppuku, seppuku carried out as capital punishment did not necessarily absolve the victim's family of the crime.