I don't know for sure but I sort of always assumed that when it comes to alot of the eastern martial arts skills which involved duel weilding with weapon including Kama,tonfas and stuff like that I sort of think that despite the fact that doing so might have been a popular training method I also don't think that alot of people who trained that way historically necessarily expected that they will always have two weapons available or within reach to fight with both at once.