The first film debuted in 1969, Crimson Bat, the Blind Swordswoman. That’s the twist. It’s a blind swordswoman instead of a blind swordsman. Yôko Matsuyama stars as Oichi, a young woman who was abandoned as a child, blinded by lightning bolt and raised by a foster family. The foster family is murdered by a bad guy, Oichi is saved and later trained by a wandering samurai who also left her after she got better with the sword than him. She was also hinting at marriage which might have had something to do with it. The rest of film has her wandering from town to town saving people and kicking butt.
Shochiku quickly pumped out a sequel in the same year called Trapped, the Crimson Bat where Oichi fights an evil female bounty hunter who uses a whip. This was followed by the less successful Watch Out, Crimson Bat and the last movie is Crimson Bat – Oichi Wanted, Dead or Alive (1970). Apparently in 1971 there was a 25 episode TV series and then the character faded into obscurity. The films have never had a North American release although there have been random versions released in other countries with bad dubs. A search on the interwebs finds nothing physical to buy in terms of DVDs or Blu-rays but apparently some of the sequels are available on Hulu if you live in the U.S.
In 2008 Shochiku produced an official female spin-off film from Zatoichi called Ichi which is about a blind swordswoman who is looking for Zatoichi. It was all right but there is something a little more entertaining about the Crimson Bat series. Maybe it’s the lower budget, the ’70s music and the gratuitous blood but it’s an entertaining time killer.