Something that bugs me is lack of research. Especially when it comes to weapons, as they are so very easy to research. The latest thing that I've seen blatantly misrepresented is the sai. So here is a short fact-file on sais.
Name: Sai (singular or plural), sais (plural, though as mentioned the extra s is not really needed), zai (more than one pair). Sai and sais are both pronounced "say".
Type: Large dagger, commonly the length of the distance from the centre of your palm to your elbow rounded up to the nearest available size (usually 15" or 18").
Description: Commonly blunted centre point between the two sides of the curved(-ish) shaft (the ends of which also tend to be blunt) which usually face the same direction (the same way as the centre point) but may face in opposite directions. Usually used in pairs.
Historically used: For the arrest of criminals and for crowd control.
Primary Uses: - Jabs and strikes to the solar plexus
- Catching swords between the shaft and centre-point
- Concentrating punches with the handle.
Can be used offensively - and even lethally - but is also a defensive weapon.