Went out for yakitori last night with a bunch of old timers. They were telling me when the officials decided that Kansai region was to stand on the right, train staff were using loud speakers and crowd control officers to "encourage' people to stand on the right.

Ever since then, everybody just stands to the right.

However in Tokyo, from the days of the samurai, way the swords were tucked away, they did not want anybody to accidently bump into it so they stand on the left.

Don't know how much of this is believable or if it is the sake and yakitori speaking but that is what they told me.