This is a good article about Japanese (not Chinese or Tai Chi) fan, or Tessen. I recently had someone tell me that a fan is only a slashing weapon; while that's mostly true in soft styles, it is not at all true of Tessen as used in Japan by Samurai. Unfortunately, I wasn't in an environment where I could spend time educating the gentleman. In Japan, the iron fan was used more for striking and jabbing, as well as joint locks. Open fans were used to strike with the edges (not just the tips of the staves), as shields, and to distract; closed ones for joint locks, strikes, and jabs. The staves were rarely sharpened. While the original iron fans were far heavier and more rigid than my kata fan, the kata fan, even when open, can deliver a painful strike. The hand position locks the fan open to make it more rigid in order to deliver a harder blow; also, the speed of the strike determines the power of the blow, just as the speed of the strike determines success in breaking boards.
The Daito Ryu Aiki Bujutsu Web Site - Tessen The Iron Fan
The Daito Ryu Aiki Bujutsu Web Site - Tessen The Iron Fan