Japan has a culture unlike no other. Historically speaking, the alternation of influxes of influence and isolation have meant that the nation's customs, some traditional, some Chinese, some American, have organically developed into the current Japanese way of life. Despite the history and homogeneity of their people, Japan is an extremely tolerant and accepting nation. With a reputation that travels far beyond their coastal borders, the Japanese people are globally renowned for their hospitality, kindness and care.
You might experience this as soon as you arrive; if a Japanese stranger sees your bulging backpack and bewildered expression, it is very likely they will come to your assistance, keen to practice their shaky English. You might experience it in Tokyo's famous nightlife; in the Roppongi district, the highlight of some young Japanese is meeting foreigners for a drink and a dance (See Nightlife in Japan). Obviously the whole nation won't be rushing to your aid, or to join you on the dance floor, but the Japanese reputation couldn't be more distinct from Londoners or Parisians. In return offer a Konnichiwa to say 'hello', an Arigatouor San kyuu to say thank you.
The politeness of the people permeates into many levels of this Japanese way of life. In restaurants, tipping can be seen as an insult and is not expected. In the home, it is good manners to remove your shoes and don slippers, with an extra, possibly communal pair, to be used in the bathroom. Similar courtesy extends in public. It is customary in communal baths such as Bathhouses (Sento) and Hot Springs (Onsen) to wash thoroughly before entering, as bathing is more of a social experience than a hygienic necessity.
With regards to population, it is predominantly a homogenous culture, with 99% of the inhabitants of Japanese ethnicity. Though minorities are almost completely integrated, like many other countries, Japan has three main Chinatowns, found in Kobe, Nagasaki and Yokohama. However, as a tourist, you should be prepared to stand out. For if you tread off the beaten track and out of major cities, it's possible you may be the only foreign visitor. This does not mean you should feel intimidated, even frosty shopkeepers may only be so as to cover up their inability to communicate with you. That said many Japanese people are extremely shy.
Japanese timidness quickly evaporates when faced with their favourite national amusement, karaoke. Don't be perturbed or put off by scenes of singing to crowded bars, as it is normal to hire a room out of the many-floored buildings, for just you and your friends. This means there's no excuse not to sing. Karaoke is so competitive in some places that people hire out trainers and some machines rate their singers, or give them the number of calories they burnt. Many of the karaoke bars have drinks deals called Nomihoudai, check out Drinking in Japan to learn more.
Other Japanese past times include Pachinko, a form of gambling where you drop small steel balls into machines. You might believe you're only going a cuddly toy but in reality, anti-gambling laws can easily be side-stepped, many of the locals preferring to exchange prize tickets for cash. The parlours where people go to play Pachinko are often not in the best condition and can seem quite run-down; it is a past-time of a certain generation and doesn't attract the young as karaoke and other games do.
A past with a bigger audience can be found in the game Go (?? igo). Played across the whole nation, thisstrategy based board even has its own TV show and newspaper features. You never know if it turns out to be your thing you could become a professional player. If you want to pick up some tips visit the Tennoji ward of Osaka and watch the masters at work.
Other games played in Japan include Shoji, also known as Japanese chess, or Mahjong, the traditional Chinese board game.
It is not only the Chinese who influenced Japanese amusements; American influence brought Japan the sport of Baseball. Since the game's arrival in the 1870s it has become hugely popular; Japan is perhaps where Baseball is held dearest, outside of the United States. The rules are extremely similar, so if you know the American version it should be easy to follow. Just make sure you book your ticket in advance as games sell out fast.