The sai (Japanese: 釵, lit. 'Hairpin'; Chinese: 鐵尺, lit. 'Iron Ruler') is a traditional Okinawan stabbing weapon used for stabbing and striking. It is most famously used in ninjutsu and kobudo, but also in southern Chinese martial arts. The basic form of the weapon is that of a sharp metal prong with two curved sideprongs (yoku) projecting from the handle (tsuka). There are many different types of sai with varying prongs for trapping and blocking.