The charges were as follows: If you got an infection from a tattoo you could be put on a charge for self inflicted wounds!!!
In 1936, when fighting broke out in China, almost all the men were drafted into the army. People with tattoos were thought to be discipline problems, so they weren't drafted and the government passed a law against tattooing. After that the tattooists had to work in secret. After WWII, General MacArthur liberalized the Japanese laws, and tattooing became legal again. But the tattoo artists continued to work privately by appointment, and this tradition continues today.