Tessen were folding fans with concealed outer spokes made of heavy iron plates. Some swordsmanship schools provided training of the tessen as a weapon. Besides using the razor-sharp spokes as an attacking tool, the tessen was also used as a throwing weapon, for fending off knives and darts and as a swimming aid. Samurai could also secretly take them to places where overt weapons were not allowed.[info sheet from distr.]