Hensōjutsu (変装術) was a Japanese martial art skill involving disguise, impersonation, and infiltration.
[1] In some ninja clans it was known as the "Shichi Hō De" (七方出), or "seven ways of going" (one form of ninjutsu that has a person play a role much like an actor does in impersonating people).
A ninja had to appear either as a priest, samurai, merchant, craftsman, performer, puppeteer, or farmer.
Ninja thus sometimes carried one or two costumes to look like the other classes and kunoichi were specialists at Hensojutsu due to the importance of close contact missions.
It is heavily reliant upon shadows and form manipulation..such as crouching to resemble a rock, twisting to match a bush, and also includes various ways one can "meld" into foliage to virtually disappear.