Have you noticed when...

When Seibei Iguchi went to visit his good pal Iinuma to find out if something bad had happened to him (during the power struggle between the Castle Warden and the reformists), Iguchi had his long katana held on the right hand when it was clear to the viewers that he is right-handed.

I read that it was customary to un-equipt the katana and hold it on the right hand upon entering someone's house. If it was held on the left hand it was considered impolite and distrusting since holding it on the left hand facilitates unsheathing the katana, unless the samurai is left-handed.

Also, it was considered an serious offense to hit, whether accidentally or not, other samurai's sheath, when walking on the street. This is why since the Edo period in the 17th century it was implemented that people walk on the left side of the street to avoid sheath-hitting incidents (could result in fatality at worse I'd imagine). This has come to be the origin of Japan's left-hand traffic, even though it is not a member of the Commonwealth.

Thought it was interesting to share this.