Size: ３６ｃｍ (Width) X ２５ｃｍ(Height) X  ３．３ｃｍ(Thickness) 

The han is wooden board, that is hung outside the meditation hall. 
The han is struck three times a day. The first time at daybreak, secondly in the evening, and finally during the closing ceremony. A wooden mallet is used to strike the familiar 7-5-3 pattern with the accelerating rolls in between. The sound is harsh and somewhat unsetteling, trying to remind us of the very reasons we came to study Zen.