High school girls wielding deadly yo-yo's! What more do you need to know. Sukeban Deka was practically a franchise in Japan from the mid 1970's through the 1980's. First as a manga, then as a TV series for three years and then two or three or four films (it is confusing). There was also a rather fun 2006 film titled Yo-Yo girl.
The Sukeban Deka story is about high school girls who work for a government security agency and are trained and armed with these yo-yos that can be killing machines or bring down helicopters. In the TV series the Sukeban Deka girl changed from year to year though there is some continuity and this film was produced the same year in which the TV series ended.
Yui Asaka who had been in one year of the TV series plays Saki, a former Sukeban Deka agent who has retired to focus on studies and teddy bears. She gets entangled in a situation and has to return to the way of the Yo-Yo to stop a madman from overthrowing the government. So she gathers a few other retired agents and they invade a fortress with a plethora of brainwashed killers.
Ok - so this is all pretty silly and I expect the target audience was teenage girls - but it is so unique to Japan culture that I could not pass it up
II - 1988
In the second film of this franchise that includes manga and a TV series, the focus shifts to one of the girls who helped Saki in the previous film. This is Yui Kazama played by Yui Asaka who also is in the third film. Like the first this is all rather foolish fun with girls with yoyos battling one another and tanks and such. Yui has been assigned to the Juvenile Law Enforcement Division whose task is to bring down crime by delinquents. The group has a few members of the Sukeban Deka all deadly with their yoyos. Too deadly as far as Yui is concerned as they don't hesitate to kill anyone bending the law a bit.
So she hands in her yoyo and heads for the hills but comes back to settle scores when a friend of hers is killed by this clearly fascist group. They have plans to take power - all 40 of them - and it falls to Yui and her yoyo to stop them. Have Yoyo Will Travel. Though I find these films just goofy fun, they take themselves deadly seriously with a lot of melodrama thrown in. And a pop song or two of course. And girls in high school uniforms. And bad guys with evil laughs.