Shoes are worn outdoors only.
Japanese people take their shoes off at the entrance hall. In Western nations, it’s common to use mats right before going inside to remove dirt from shoes. In Japan, you step up to an indoor level from outside. Also, front doors in Japan open out to make space for people to take their shoes off and leave them before stepping up.
Hold your rice bowl in your hand.
When eating traditional Japanese cuisine, you are supposed to hold your bowls (such as rice bowls and soup bowls) in your hands. Not doing so is considered poor etiquette.
Number 4 is bad luck.
It is a superstition, but Japanese people dislike the number 4 because it is pronounced as “shi” which also sounds like death. It’s not uncommon to skip apartment numbers that include fours. When purchasing a gift, it might be good to avoid a set of 4.
Let’s not eat while walking.
Traditionally, eating while walking is considered poor etiquette. You are also expected to refrain from eating on public buses or trains. The only exception to this rule is ice cream, which is considered acceptable to eat while walking.
Please only use restroom slippers in restrooms.
Since you are expected to take your shoes off indoors, individual homes and some establishments such as restaurants, temples, etc. have slippers available for you to use indoors. Furthermore, there can be separate sets of slippers used only for restrooms. It’s important not to step in a restroom wearing regular slippers.
Tips are not expected.
Many nations have the custom of paying tips for hotel doormen, tour guides, and wait staff in restaurants. There is no tipping custom in Japan. Even when someone demands a tip, you do not need to oblige, as it is not a custom.
Please do not blow your nose in public.
People regard blowing your nose in public rude and they feel disgusted by it. Most Japanese look for private places to blow their noses or simply endure their discomfort. If you must, try not to make too much noise. Also, please use tissues and not your handkerchief.