This kind of tattoos are called the Ainu. Tattoo had quite different purpose in the past, and in some cultures it still keeps its primal function, and that is the protection. Tattoo was used for protection rather than decoration; in particular for protection during pregnancy and birth when woman is exposed to most risk. During a pregnancy, the net-like pattern of the tattoo would expand across the stomach protectively, and figures god would sometimes protected women during childbirth, were tattooed on their thighs. All of this was meant to keep children healthy in the womb and protect both mother and child during pregnancy and childbirth. Hey, if you don’t have a doctor, you’ve got to do something, right?