Kyosaku or Keisaku:

95 cm long encouragement stick.

Blank raw ash wood.

This encouragement stick or warning stick is used in the zendo (meditation room) to stimulate blood flow in the back muscles and relieve tension.

In Zen Buddhism, the kyosaku or keisaku is a flat wooden stick which is used during periods of meditation to remedy sleepiness or lapses of concentration. This is accomplished through a strike or series of strikes, usually administered on the meditator's back and shoulders in the muscular area between the shoulder and the spine. The keisaku itself is thin and somewhat flexible; strikes with it, though they may cause momentary sting if performed vigorously, are not injurious.