Legend of Kamui is a legendary ninja manga created by Shirato Sanpei in 60s. Set in feudal Japan this manga is social commentary on class struggles and oppression of minorities, a collection of historical facts, ninja lore, and graphic violence. Shirato's ninja are more historically corrcet and realistic than the image popularized in western movies. His ninja don't spend all of their time in black garb, but use those mental tricks used by historical ninja to forge their mysterious reputation.
Kamui is born in a buraku, a community of traditionally discriminated people in Japan's Edo Period. And so his story becomes a canvas on which Shirato depicts problems of discrimination, oppression, exploitation and the absurdity of feudalism, indirectly commenting on present day problems as well. Kamui grows up to become a ninja, mostly to escape his peasant/burakumin origins, but realizes that this is not what he really wants, and so he ends his training, leaves his clan and becomes a nukenin (a ninja outlaw), hunted for leaving his clan, never knowing whom he can trust, and who is just another ninja on his trail. The series is a classically constructed, lyrical and melancholic work. It has a nobility of spirit found in little other series and so the reputation of the author is well-earned. In fact, Kamui is so well known in Japan, that it was discussed in universities by staff and students alike and was a topic in many intellectual discussion circles. In fact, there are few Japanese that do not know about Kamui, and have read the books at some time.
Apart from the story, the art is great as well, the backgrounds and sceneries are depicted very detailed and realistically. The characters are very dynamic, and the action-scenes forceful and energetic. In fact, when moving, characters become shadows, mere streaks of movement, flashes of momentum full of energy. Some of the art may seem familiar, in fact, which is to be expected, as part of the later artwork in Kamui (specifically Kamui Gaiden Dai 2 bu) was actually drawn by none other than Goseki Kojima, who drew all the art in Lone Wolf and Cub.
The full story of Kamui is told in three series, which are:
Kamui-den (Legend of Kamui), originally serialized in Garo and collected in Golden Comics, 1964-71.
It's 74 chapters were collected in 21 tankobon volumes or 15 bunko volumes.
Kamui Gaiden (More Legends of Kamui), originally published 1965-1967. There were two volumes.
Kamui-den Dai 2 Bu (Legend of Kamui, Part 2), also published in Golden Comics, from 1988-?.
There are 22 volumes up to now. It is a collaboration with Tetsuji Okamoto.
Kamui Gaiden Dai 2 Bu (More Legends of Kamui, Part 2), originally published 1982-1998.
There were twelve volumes, the art was drawn by Goseki Kojima.
As for foreign editions, I know of a two-volume series, in nice big format, which tells one story from the middle of the saga, from Kamui Gaiden 2, to be precise. This story has been published in the US as well as in Germany, maybe elsewhere as well. These books are a nice view into he world of Kamui. In the story, he temporarily finds safe haven after being taken in by a community of fishermen on a remote island. But the respite is only of short duration. Furthermore, there is a animated movie known as Dagger of Kamui (also The Blade of Kamui and Revenge of the Ninja).
The series has even been adapted into a television series in 1968. Check it out...
A very nice webpage on all the series can be found under the following address. It is in Japanese, however:
http://homepage1.nifty.com/kumori-hibi/sirato01/sirato01.html