J. Akiyama wrote on Aikido-L:

I don't think the protocol changes as far as I know -- lefties (those sinister people) are supposed to conform to right-handedness. Conformity -- that awful Japanese quality...

I don't know -- maybe we as a race didn't think it fashionaby correct or something to be a left-handed swordsmen. I think it would have been tactically an advantage, but who knows?

Actually, there is a good reason for not carrying your sword on your right hip.

In Japan, we walk on the left side of the path since we are a sword culture. If you had your sword on your left hip and walked on the right, you would be continuously banging your sword against someone else's or against their leg. To avoid that problem, everyone (except for those infernal 7% southpaws) walks on the left.

However, if a southpaw wore their sword on their right hip and walked on the left, they would be banging someone else who would then draw their sword and kill the southpaw. Could the southpaw defend him/her/itself in time? I doubt it. Drawing a sword with your right hand to cut the do of someone on your right is a very natural and direct cut. The southpaw's quickest attack would be to draw from the saya and thrust straight back--a slower and less direct move than the right-hander's cut. Yes, there is the turning away the sword side do cut but it is still not as fast as the one in which the non-sword side is pulled away as in the second kata requirement for many iaido ryu. Perhaps all the people who insisted on carrying their swords on their right hip were killed off due to this reason? Maybe that's why Japan has so few southpaws?

However, given that, there are forms for the jo in which the hand positions are switched for the yokomen attack on either side in order to get the best distance advantage of the jo.

Rock

First, there were very few left-handers in old Japan. Genetically, they made up only about 7 percent of the population. Furthermore, everyone that was born left-handed was made to be right-handed for a couple reasons:

1. It is difficult, if not impossible to write Japanese left-handed. Good penmanship requires that you write right-handed. Good penmanship was, and still is, an indicator of your level of upbringing. Poor penmanship was thought to go with poor thinking processes and a lack of education. If you weren't right-handed, you were made to be right-handed or you were a social outcast.

2. Kimonos are put on as if you were right-handed. The left flap goes over the right so that you can reach inside to get your tissues or fan or tanto or whatever was stored in the flap. The only time the right flap went over the left was in your burial kimono. If you wore your kimono in a left-handed fashion, you were already dead. If you wore your kimono right-handed and wore your katana left-handed, the tsuba would catch on your kimono and you would be further dead. If you wore your kimono left-handed and you wore your katana left-handed, you would look like an idiot and no one would anything to do with you.

3. If you wore your katana for a left-handed draw and you walked according to convention so that you passed on the left, you would always find your katana in everyone elses' way. You would be a social idiot and I don't think anyone would complain if someone cut you down.

4. As in most cultures that had horses, they were generally mounted from the left side so that you could use your right arm and leg to get up. All horses would be trained that way. Try getting up on a horse correctly when your katana is getting in the way because you are wearing it on the wrong side.

5. If several people had to sit in a war conference next to each other, if one person had their sword on the wrong side, it would inconvenience everyone else.

Rock