Kiri sute gomen (斬り捨て御免 or 切り捨て御免: literally, "authorization to cut and leave" (the body of the victim) is an old Japanese expression dating back to the feudal era right to strike. Samurai had the right to strike with sword at anyone of a lower class who was compromising their honour. This applied to higher ranked samurai striking lower ranked samurai.
Because the right was defined as a part of self defense, the strike had to follow immediately after the offense, meaning that the striker could not attack someone for a past grievance. Also, due to the right being self defense, it was not permissible to deliver further coup de grâce. Moreover, the samurai who exercised the right had to prove the correctness of his action in court by producing a witness. Punishment for the incorrect exercise of this right was severe. An offender could be beheaded without being allowed to commit seppuku and have his house abolished, meaning that one of his sons could not succeed the title. Due to the seriousness of the punishment, many committed seppuku to pre-empt the verdict. A samurai visiting a different feudal province had to be extremely careful, especially if it was in Edo, the seat of Shogun. Wrongful executions of commoners from different feudal provinces were seen as an offense against a feudal state. It was thus advisable for samurai visiting different provinces to be accompanied by his servant, so as to provide witness.
Because of somewhat arbitrary nature of this right, anyone who was at the receiving end had the right to defend themselves by wakizashi (short sword). This situation was most common in the case of a higher samurai exercising the right against a lower ranked samurai as samurai would always carry wakizashi. In one well known incident, a commoner bumped into a samurai. The samurai pointed out the disrespect but the commoner refused to apologise. Feeling merciful, the samurai offered the commoner his wakizashi so he had a chance to defend himself. Instead, the commoner decided to run away with his wakizashi, causing further dishonour. The incident resulted in the samurai being disowned from the clan. He later regained his honour by seeking out the commoner and killing the whole family.
The expression is still sometimes used in modern day as "I apologise in advance for this one" for the subtle humour in offering what amounts to an unsympathetic apology.
It is used in the James Bond novel You Only Live Twice, where the villain Blofeld asks of Bond: "Have you ever heard the Japanese expression kirisute gomen?", who replies with: "Spare me the Lafcadio Hearn, Blofeld."
"Kirisute Gomen" is also the title of a song from American heavy metal band Trivium's fourth studio album Shogun.
John Pierre Mertz, "Tokugawa Cultural Chronology", (version 2008.01.30; www4.ncsu.edu/~fljpm), page 2. Retrieved on 2008-08-16.