How did Japanese Samurais who brought dishonor to their masters commit harakiri?

In the movies, harakiri appeared very real.

Realistically, it’s not clear how often the practice of ritual suicide—or seppuku—was voluntarily carried out to clear a samurai’s honor.

The practice was more frequently used as a form of punishment, not as a completely voluntary act. What was involved is also often portrayed inaccurately:

After donning white clothes and ritually washing himself, the warrior wrapped his sword in paper, then cut his own abdomen, an act generally called hara-kiri (loosely translated to mean “belly” and “cut”; maybe from the Japanese verb kiru: “to cut”).

Following this, to end his excruciatingly painful suffering, the warrior’s most trusted friend would chop his head off from behind.

Seppuku would then be complete, and not a minute too soon.