Do not shake hands when you greet; instead bow with your palms on your thighs.
People are judged mostly by their behavior during non-business hours, even in the business world.
Drinking is a group activity, with toasting being very important. Do not refuse drinks. If you do not want anymore, keep your glass half full.
It is acceptable to slurp noodles.
When doing business in a meeting or a business room, wait for the person who called the meeting to give instructions to sit down before taking your seat.
Receive and present gifts and business cards alike with both hands. Receive with a bow. Do not give gifts if you don’t have something for everybody in the situation.
Business cards are extremely important to the Japanese. When you receive it, hold eye contact, and do not write anything on it.

https://www.cia.gov/library/publications/the-world-factbook/geos/ja.html (Majority of information)
http://www.stat.go.jp/english/data/nenkan/pdf/yhyou02.pdf (Ethnic data)
http://worldpopulationreview.com/countries/japan-population/cities/ (Tokyo population)
Wolfram|Alpha (Currency exchange data)
Information accurate to best of ability as of 9 November 2016
¹ Japan does not collect ethnic data, this information is by nationality. Due to Japan's homogenous population structure, this is quite accurate in terms of describing ethnicity.