In Japan, there is no urge to fill the silence with talk, but rather to use it a time to consider what is being said. It's considered rude to sit with legs crossed or slouched. The proper way to sit is upright with both feet on the floor.
Crossing your feet in some cultures is considered very rude. In Japan you are expected to sit erect with both feet on the floor and never cross your ankle over your knee.
Sitting with legs crossed (offensive in Ghana, Turkey)
The whole reason crossing your legs is seen as poor manners on Japanese trains is because it takes up more room that siting with your legs uncrossed. In other words, choosing to sit with your legs crossed is choosing to sit in a way that takes up more space than you would otherwise.
'proper sitting') is the formal, traditional way of sitting in Japan. It involves a specific positioning and posture in a kneeled position so as to convey respect, particularly toward elders. It developed among samurai during the Edo period and was later widely adopted by the public.
Sitting. Typically the Japanese eat at low dining tables and sit on a cushion placed on tatami floor (a reed-like mat). In formal situations both men and women kneel (“seiza”), while in casual situations the men sit cross-legged and women sit with both legs to one side.
What is Seiza? Based on ancient Japanese standards, Seiza is considered the formal way of sitting. The term translates to “sitting with a correct posture.” The position is characterized by neatly folded legs, an erect spine, and feet neatly tucked underneath the body.
Showing someone the bottom of your feet is considered rude. When you talk with Japanese people, they will say your name with “san” at the end (a term of respect and honor). However, do not copy them by placing “san” after your own name when you refer to yourself.
Not Being Noisy on the Train is an Iron Rule
There is no rule against talking in the train car, but if your conversation is loud enough to be heard by those around you, it is considered rude and annoying. Japanese consider discussing private matters in public to be unseemly and rude.
Never talk on your phone while on the train, unless using the designated phone area of the shinkansen. Silence and use headphones so that your media cannot be heard by others. Finally, turn your phone off if sitting near the priority seating area.
Comfort: We tend to cross our legs when we feel comfortable, confident, and relaxed. For some people this is a naturally comfortable posture, and women who wear short skirts will often cross their legs. Others will cross to shift their weight if their legs are feeling tired.
Depending on the context, sitting cross-legged can mean a person is either relaxed or defensive. Body language experts note that if you see someone sitting this way in a meeting, it may indicate they have emotionally withdrawn from the conversation.
It can also cause greater trochanteric pain syndrome, a common and painful condition that affects the outer side of the hip and thigh. Research also shows that sitting with legs crossed can put the peroneal nerve, also known as the fibular nerve, in your lower leg at risk of compression and injury.
Avoid physical contact. Nose blowing in public is considered very rude, as are yawning, coughing and using toothpicks without covering the mouth.
Making eye contact is considered rude, leads to uncomfortableness, and can be construed as a sign of aggression. When speaking to or approaching a Japanese individual, make very brief eye contact to signal the individual, but then maintain appropriate eye level, such as the individual's neck.
Note: It is very rare for anyone to acknowledge a sneeze in Japan, and it is customary not to say anything at all. After multiple sneezes, they use these words. "Are you all right?" "Sorry." or "Excuse me."
Japanese tend not to eat while walking along or standing around on the street. However, it is acceptable to drink while standing aside a vending machine. Eating and drinking on local trains, but not long distance express trains, is also frowned upon.
Talking on the Phone
You can use the phone for texting or surfing the internet, as long as it doesn't make any noise. If you want to listen to music, you should wear headphones.
Others are manner rules universal: don't speak with your mouth full, and close your mouth while you are chewing. What's special for Japanese food is perhaps the use of chopsticks.
If you are not wearing socks, it is polite to bring a fresh pair of socks to wear after removing your outdoor shoes because entering someone's house barefoot is not considered well mannered, although acceptable in informal situations. Slippers can generally be worn anywhere except when entering rooms with tatami floor.
Always finish your meal!
The Japanese consider it rude to leave food on your plate, and even more so to order more food when you haven't finished everything you've already got. This is related to one of the fundamental concepts in Japanese culture, mottainai, which is a feeling of regret at having wasted something.
Showing Respect. In addition to the practical reasons, taking off your shoes is also seen as a sign of respect when entering someone's home or place of business. Traditionally, it could be seen as disrespectful to keep your shoes on in someone's residence.