("Nihon" as a nation
, "Nippon" as a state
) is ancient, powerful, and infinitely interesting.
Physically speaking, Japan is a collection of over 3,000 islands scattered in a line more than 2,000 km long, stretching from icy Sakhalin and the Kuril Islands all the way to tropical Taiwan, and including some outlying chains such as the Bonin Islands and Volcano Islands. Most of Japan's population, however, lives on the four largest islands: Honshu in the center, Hokkaido in the north, and Kyushu and Shikoku in the southwest.
And what a population it is! There are over 125 million people in Japan: that's half the population of the United States, living in an area the size of California. However, because most of Japan is mountains (many of them volcanoes), the real livable space is much less than a political map might indicate. Let's talk about these people before we talk about anything else.
Japan is very homogeneous yet very unique, and that's probably why the fascination with everything Japanese is so strong in so many people. Samuel Huntington identified Japan as the only state on Earth that constitutes its own civilization. It has a unique language, religion, and social system that fill the entire country, yet do not overflow its borders. Were it not for a sizable foreign population in Japan, and a sizable Japanese population abroad, the little group of islands would be a perfect nation-state, a political entity congruent to a social entity.
However, the Japanese have imported much of their culture from other countries. The writing system, kanji, was imported from China, and the "other religion," Buddhism, is also an import. There are many European influences as well: Japanese education was largely based on the model of Germany, and the governmental structure drew heavily from the example of Britain.
Stereotypically, the Japanese are obsessed with hierarchy, discipline, and honor. In reality, while these concepts are fundamental to Japan's society, they are not as apparent today as many Westerners allege.
Transience, however, characterizes the Japanese nation fairly well. Some say that it comes from the teachings of Zen: others argue that Japan's history is simply one of constant devastation and rebuilding, whether from earthquakes, civil wars, or atomic bombs. Whatever the cause, Japan's cities all looked totally different a decade ago, and will probably look totally different a decade from now: that's how the country works.
Shinto gives Japan a natural air. People leave their windows open during the summer, rather than use air conditioning. Japanese literature is obsessed with sakura, autumn leaves, snow, and the other signs of change in nature (which connects back to the transient cornerstone).
But Japan is not Bhutan. Its people wear suits and ride the subway to work: indeed, they are the third-wealthiest people on Earth, after Luxembourg and Switzerland. They all have mobile phones (which are years ahead of what you're using in any other country), and they all watch television and movies, and drink Coca-Cola and Pocari Sweat and Nescafe, and do all the same pointless societal motions that are found in North America and Europe. It's probably safer to say that the key to understanding Japan is understanding wa, "harmony," which is so central to the concept of Japan that its kanji is often used to refer to Japan!
Despite these overtones of harmony, Japanese history is a history of civil war up to the late 1800's. The few men who make decent claims to having unified Japan—Tokugawa Ieyasu, Toyotomi Hideyoshi, and Oda Nobunaga—never quite achieved their goal: instead, they managed a complex confederation of samurai fiefdoms that never coalesced until the arrival of an outside foe. For these three men, that outside foe was the Christianity of Francis Xavier and the Roman Catholic Church. Perhaps the most unique and pivotal point of Japanese history was that the entire country was closed to foreigners for more than two centuries, after Tokugawa consolidated his power against the Christian threat.
The modern Japanese state was formed by the Meiji Restoration of 1868. Meiji was the emperor of Japan at the time, but he was not an absolute monarch: rather, he was a spiritual leader, with only limited authority to halt the temporal actions of the samurai, and their periodic bakufu governments. From 1868 through the end of World War II, the Emperor's power was consolidated within the newly christened Japanese Empire, with a weak parliament, the Diet, serving as the instrument of the former samurai class.
World War II marked Japan's first, and only, military defeat in recorded history. The Allied Occupation of Japan sought to change Japan to make it an egalitarian democracy, but had to quit early when the Korean War broke out. Today, the Emperor is only a powerless figurehead of the Japanese state. In theory, the Diet now holds virtually all of the governing power, but in practice, it is the highly intertwined world of the "kanryo" bureaucracy and the many Japanese mega-corporations that run the show. Their efforts were wildly successful at first, shoving Japan into a bubble economy juggernaut that promised to make it the foremost economic power in the world. However, things fizzled out in the 1990's, and now the government and industry are merely plowing through the wreckage of a stagnant economy.
Still, Japan has the second-highest gross national product on the planet. Its heavy industries are almost unparalleled the world over, renowned for their efficient production of cars, electronics, appliances, chemicals, and steel, among many other things. Even in its current period of budget deficits and economic slump, Japan maintains a sizable trade surplus of nearly $100 billion, mostly importing oil for its industries and food for its people. Japan's keiretsu conglomerates are among the largest corporations on Earth, and Tokyo houses three of the world's five largest banks (Mizuho, Sumitomo Mitsui, and Mitsubishi).
The Liberal Democratic Party, Japan's dominant political force since the 1950's, represents conservatism and protectionism, which is what brought Japan's economy to these great heights after its stunning defeat in 1945. Whether conservatism and protectionism will save Japan now is anyone's guess.
Tokyo is sometimes incorrectly seen as the primate city of Japan. In reality, the lion's share of Japan's population is divided between two humongous urban sprawls. Tokyo, Yokohama, Kawasaki, Chiba, and Saitama blend together to form a mega-city of 30 million people around Tokyo Bay ("Kanto"), while Osaka, Kobe, Kyoto, Nara, and Wakayama account for another 20 million-strong metropolis in central Japan ("Kansai").
The Kansai region was the political, economic, and cultural center of Japan for centuries, until the Tokugawa shogunate moved political affairs to Edo, and gave Japan its own great cities dichotomy. Until well after World War II, Tokyo was perceived as the political center of Japan, while Osaka was the commercial center: the collusion of government and business after the war changed that, and now Tokyo and Osaka are equals from a business perspective.
There are other major cities, too: Sapporo, Sendai, Niigata, Nagoya, Hiroshima, and Fukuoka are humongous in their own right, although they lack the power of the Kanto and Kansai sprawls.
And Japan is not entirely urbanized. There is still a sizable population living in the boonies, mostly consisting of rice farmers who receive healthy subsidies to continue their age-old craft on tiny plots of astronomically expensive land. Japan also has many national parks and forests, mostly in mountainous regions that aren't conducive to urban development.
Trains and buses are the predominant mode of transportation in most of Japan: expressways are a relatively recent phenomenon, and most charge hefty tolls. The high-speed JR Shinkansen train is the centerpiece of the transportation network today: if you can't get there on the Shinkansen, you can fly there on any of Japan's three major domestic airline systems.
Most Japanese people live in cramped quarters. The less well-off have tiny apartments, and the upper middle class get tiny houses. Part of Japan's reliance on wa is a result of people having to live so closely together.
Japan is a real country: it's not an ideal. Most of what you've probably heard about Japan is exaggerated. The women are not all beautiful, the streets are not all clean, the temples are not all harmonious, and the people are not all friendly.
However, you can walk around Tokyo at night without getting mugged, and you can leave your bicycle unlocked in the street and not worry about it getting stolen. You can ask random people on the street for help, and they will almost always stop to help you. You can stay at someone's house and expect royal treatment: you can respect someone and expect them to respect you back.
In some ways, Japan gets more to the point of being human than any other industrialized capitalist state manages to. And while the air pollution can kill you and the stigma of being a gaijin can smother you, you'll more than likely find something about this little cluster of islands to fall in love with.