If you read up on your sai history, you would find out that some would carry a third sai by the belt. This sai would be used as either a back up sai or a throwing knive. If you also notice the Bo looks strangly like the spear, so I'm guessin if you think about it the Bo can be thrown also. If you read up a little bit about blocking then you can find out that if a bo is thrown at you its not that hard to knock it out of the way. a sai on the other hand would move much faster and it would spin so with a bo it would be less easy to block it. So I say on a distance the sai would probly win depends on whos the fighter! Close up, With Bo you cant do much maybe hit 'em up side the head. with a sai theres wrist grabing knocking eye gouging weapon taking you name it pressure points you could stab even tho the origanal sais were not used for stabing, I'd have to say sai is the better of the to. Its sad really, the BO is my favorite weapon.
