Originally Posted by pravnik
The explanation I've always heard was because samurai wore them that way because they carried the katana and wakazashi in the obi on the left hip, and the rest of Japanese society followed their lead. If the kimono is folded right over left, the hilt can get stuck and tangled in the fold during drawing, not something you want to happen when clearing a weapon for immediate use.
The problem with this explanation, though, is that this tradition comes from China, not Japan, and is also about 3,000 years old or so. I don't know when exactly it became fixed that you only wear your robes left over right, but for example, if you look at pictures of the Terra Cotta Warriors of Xian, it's already well established in 210 BC. The samurai didn't arise in Japan until about 1,000 years later! I'm not sure you can apply the same weapon hypothesis to the Chinese because I don't think they carried their weapons the same way as the samurai. In most depictions of Chinese warriors I've seen, they're either carrying their weapon(s) in their hands with no sheath to speak of, or the sheath is just hanging from the belt. Admittedly, it's hanging on the left side, and while you might still be able to make the argument that folding one's clothes left over right makes it easier to draw, something makes me feel like Chinese people were probably wearing clothes that way well before they started hanging swords off their belts. Furthermore, Chinese armor fastens up the middle, getting rid of any possible sword-getting-caught-in-fold problems, and I'm not sure if Chinese warriors were constantly armed in the same way as the samurai (they could have been. I just don't know). If they only hung swords off their belts when they were wearing armor that fastened in the center, why would that have affected how they wore their robes?
As for the general "it's nice to use the fold as a pocket" argument, I guess that's possible, and while it's true that many people do stick stuff in there, it's also true that people also carry around special bags when wearing kimono/yukata. (Ex: http://terwee.takm.com/Aug02/Ladies%...g%20yukata.jpg
It's possible that people starting carrying bags because they didn't want to stick things in the fold anymore, but even if that's true, why wouldn't left handed people fold their robes the other way? Unlike a western shirt's buttons, there's nothing that prevents them from folding it the other way. (Except maybe all the social pressures that force left-handed people to act like right-handed people...
By the way, does anyone know if they have similar cultural stigmas against left-handed people in East Asia as they do in the West?) Anyway, I guess I'm still not convinced that the reason folding left over right is set in stone is because it creates a convenient pocket for right-handed people. It could just be a coincidental benefit, after all. *shrugs* It's possible, though, I guess...