Seppuku is a Japanese ritual where a samurai kills himself by cutting into his belly. After one had done so, a second person would cut off his head. It was thought that seppuku was an honorable way to die. Sometimes, it is called hara-kiri, which is translated from Japanese as belly-cutting.
Seppuku was a key part of bushido, the honor code of the samurai warriors. It was used by warriors so that they would not fall into enemy hands and be shamed. It was possible also that a samurai received an order from his master to commit seppuku.
Because seppuku was an honorable act, a warrior who was caught by the enemy was sometimes given the choice between seppuku and being executed. If he chose seppuku, he could protect his honor. Samurai women had to ask for permission to commit seppuku.
This act could be performed either with a ritual, or quietly on the battlefield while other warriors fight the enemy.
The main weapon used was the samurai's knife called tantō or the short sword, called wakizashi. A samurai who wants to commit seppuku would take the weapon, open his kimono and stab the blade into his belly. He would make a deep cut from Right to left. And assistant of the warrior committing seppuku (called kaishakunin) would immediately cut off his head.