I was very surprised when I saw this movie for the first time. It contains everything exploitation movies can feature: Sex&Violence (carried out by children!)!! Probably very gross for the most viewers. The story deals with a group of children who are trained to be ninja assassins wearing demon masks and work for the shogun carrying out covert actions. The five kids receive a brutal training in the mountains hidden away from society. Once their training is complete they have to infiltrate a fief and kill the clan leader. It is a more or less simple story, which really reminded me of Kitamura's Azumi. But for the time (1974) it contains gore ,bloodshed and rape, which I thought was very hardcore - watch out for the face-buster-move(even though it is a little trashy). Koike wrote the story and it fits good into line with Lady Snowblood and Lone Wolf. Anyone who enjoyed those movies will have a hell of a time watching this one. If you don't like seeing teenagers being tortured or little children working as killers...stay far....If you are down with ninja/samurai flicks, this one is worth to be checked out!!!!