Used in Zen dojos, the kyosaku is a light stick used by a godo (or dojo supervisor) to strike those practicing zazen. The purpose of the kyosaku is to spur the sitter on, to keep them alert, bring them to the present, encourage them to push on with their meditation and check their posture. Use of the kyosaku can be accompanied by loud shouts of encouragement from the godo - "Concentrate! Stay with your koan!".
Loosely the word "kyosaku" means "stick of compassion". It can also be called a keisaku.
The kyosaku is administered to the soft parts of the back or shoulder (never on the bones) and can be swung to give anything from a soft tap to a startling blow, at the discretion of the godo. The stick gives more of a slap or whack than a thump, so while occasional minor bruising is possible, it is not the norm. It is not like a baseball bat!
Generally western society has misunderstood (and thus condemned) the use of the kyosaku in dojos. To a westerner being beaten with a stick may be considered demeaning - a loss of dignity. This is not the intention. In the words of Shinzan-roshi on tv show John Safran Vs God: "'Please beat me. Please take away my ego'. This is the attitude that is required." To demonstrate this attitude, after the kyosaku has been used on a student both the godo and student raise their hands in gassho. In this act the student expresses respectful gratitude to the godo for encouraging him on the path of enlightenment, and the godo acknowledges the student with respect and understanding.
It is also possible for a student to have a sign put above them requesting that they not be beaten, but in some cases this may only granted if the roshi agrees that the kyosaku is not helping the student's progress, or if there is a medical reason.
The godo is carefully selected by the roshi and has proven their strength of character and compassion. A skilled godo is able to perfectly select and time use of the kyosaku so as to be most beneficial to the student. The kyosaku is never used as chastisement, in anger, or for personal revenge.
Those practicing zazen often request the use of the kyosaku by raising their hands in gassho above their heads. In fact, as Zen spreads to the western world, and even as existing sects evolve, the "by request only" kyosaku is becoming more popular.
The kyosaku is used more in the Soto sect than Rinzai, where use of it appears to be waning. In Soto, students face the wall, so the kyosaku is applied from behind. Sometimes the student is given warning with a light tap on the shoulder - other times they are struck without warning.
In Rinzai Zen where students face the centre of the room, the kyosaku is used from in front of the student. Here the person receiving the kyosaku must lean forward and move their head to one side so that a clean strike clear of the head may be administered.
Kyosakus come in varying sizes and shapes. Almost all are made of wood. Hard wood kyosakus are made for winter months when students are wearing several layers of clothing. Soft wood kyosakus are for the warmer months when clothing is thinner so that it doesn't hurt. They can range in size from about 0.75 metres to almost 1.5 metres. The gripped end is round and the part that contacts the back of the sitter is flattened.
Many practioners of Zen consider the kyosaku to be a vital tool, available to the roshi to use in his dojo if he chooses. | 
