Sak Yant, Yantra Tattooing

Sak yant designs are normally tattooed by wicha (magic) practitioners and Buddhist monks, traditionally with a long bamboo stick sharpened to a point (called a mai sak) or alternatively with a long metal spike (called a khem sak).
History
Chinese chronicles describe yantra tattooing among the Thai cultures of southwestern China and northwestern Vietnam at least 2000 years ago. Over the centuries the tradition spread to what is now Thailand, Laos, Cambodia and parts of Myanmar. Today it is most popular in Thailand, whereas in Cambodia and Laos the tradition has almost completely vanished.