Japanese, like any language with a large number of speakers scattered over a wide area, has a number of dialects, known as ben (弁) in Japanese. However, unlike the widely varying and mutually unintelligible Chinese dialects (which would be different languages if not for politics and a unified orthography), the differences between Japanese dialects are for most part quite minor and on par with the regional dialects of English in the United States. In fact, Japanese dialects are slowly converging, since thanks to the advent of mass communications all Japanese now understand and speak standard Japanese, and new vocabulary is instantly disseminated throughout the country.

Standard Japanese (標準語, hyôjungo) as spoken by TV newscasters is based on the Kanto dialect spoken in Tokyo and the great eastern plain that surrounds it. While hyôjungo is pretty much carved in stone, there is also a Tokyo dialect (東京弁, Tokyo-ben) that reflects the way the youth of the great city speak; probably the easiest identifying feature is the use of -jan ("right? isn't it?") instead of "-ja nai".

The next most important dialect is undoubtedly the Kansai dialect (aka the Kinki dialect, Jp. 関西弁 Kansai-ben), spoken in western Japan in cities such as Osaka, Kobe and Kyoto. (See the node for details and examples.) This in turn is split into several subdialects, most notably the gruff Osaka dialect (大阪弁, Ôsaka-ben) favored by Japanese comedians and gangsters, and the effete remnants of Imperial court splendor mouldering as Kyoto language (京言葉. Kyô-kotoba) -- and note that Kyotoites insist on calling it a language, although the only difference most mortals will encounter is the use of Oideyasu for "Come in!" instead of the normal Irasshai(mase).

And that's it as far as respectable dialects go: speaking anything else will brand the speaker as a country bumpkin, or actually a country potato (inaka no imo), as the Japanese like to say. But them potatoes are a hardy lot and their dialects prosper just the same...

The dialects of Tohoku, up in the northeast of the main island Honshu, are collectively known as Tohoku-ben (東北弁). The dialects are also somewhat derisively dubbed zuuzuu-ben, since its speakers like to substitute s with z. Other noteworthy oddities include the use of the particle sa to mean direction and the nonstandard helper verb -bee (from. beku) to indicate intention, as in Tôkyô sa ikubee, "I'm going to Tokyo".

Going down south, Shikoku has a large variety of dialects, the best known of which is Tosa dialect (土佐弁, Tosa-ben, Tosa being the old name for the modern-day prefecture of Kochi). The dialects are all clearly related to Kansai-ben, but add on additional weirdness like tacking on the particle -ken at the end of every other sentence.

Hopping down one more island, Kyushu's dialects are positively infamous and the dialect of southern Kagoshima (薩摩弁, Satsuma-ben) is widely considered to one of, if not the most, incomprehensible dialects of Japanese. Merely dissecting a typical phrase like sojantai, ata n yuugotsu ("yes, you're right!") would take up several pages...

But there is one more Japanese dialect that should, in fact, really be called its own language: Okinawan aka Ryukyuan (Jp. 琉球語 Ryukyugo, Ok. Uchinaguchi), spoken by the inhabitants of Okinawa and the Ryukyu Islands, an island chain that trails the southernmost bits of the main Japanese islands. Originally an independent kingdom, the islands were annexed by Japan in 1879 and the Imperial government of the time went out of its way to suppress any vestiges of a separate identity. The language survived best on the more remote islands such as the tiny Yonaguni, whose dialect even other Okinawans have trouble with.

And that's it. Note that the Ainu language spoken on Hokkaido is linguistically unrelated and thus not a dialect of Japanese at all.