Originally Posted by estcrh
Several forum members have mentioned China as a possibility of the origin for the sai being discussed here but so far no one has posted any Chinese sai to compare with or any reference from a book.
Here's a Chinese example (the Japanese name would be "manji no sai"; I don't know if there is a specific Chinese name, or whether it is just "cha" like a normal sai). In rather poor condition. 715g.
Pre-Meiji Okinawan sai are built much like Chinese ones. How would one tell the difference? How can one tell whether it was made where it was found? (Mark Bishop's book, "Okinawan Weaponry" has some old Okinawan sai, and notes one that might have been imported from China.)
These days, Okinawan sai are best known, but that's a result of the spread of karate and the inclusion of the sai as a karate weapon.
Also attached is a picture of an iron ruler that's half-way to becoming a sai. (Pg. 55 in 中国古代冷兵器 (Ancient Chinese cold weapon)