None of the descriptions I can find online say this, but it seems to me that I read in the DVD insert material (last time I saw this), that it was based on a serial that appeared in a Japanese magazine over a period of several years. This is one of the drawbacks of the film, unfortunately, because they tried to squeeze too much into the movie, and the plot ended up being rather choppy and confusing at times (but apparently the Japanese audience was familiar enough with the story that they could fill in the missing pieces on their own). There were supposed to be some sequels, but they were never made.
The above trailer is of bad quality, but it is the only one I can find. The film has been restored, so the quality is much better than what you see here. - DG
Edit 2010.12.28: Scan of DVD insert/essay attached.
The Sword of Doom (1966), directed by Kihachi Okamoto
Tatsuya Nakadai and Toshiro Mifune star in the story of a wandering samurai who exists in a maelstrom of violence. A gifted swordsman—plying his trade during the turbulent final days of Shogunate rule—Ryunosuke (Nakadai) kills without remorse, without mercy. It is a way of life that ultimately leads to madness.
Boasting some of the most impressive swordplay in the history of samurai epics, Sword of Doom is a visceral masterpiece of violent style and powerful substance. Illustrating the timeless adage that "an evil soul wields an evil sword," this highly stylized classic is driven by the fierce and fearsome performance of Tatsuya Nakadai as Ryunosuke, a sociopathic samurai whose soul--and sword--are vicious instruments of evil. Having mastered a highly unconventional style of fencing, Ryunosuke welcomes an exhibition match at a fencing school run by master swordsman Shimada (Toshirô Mifune, in a small but pivotal role), where he kills his opponent after promising not to. Flagrantly violating all codes of honor, Ryunosuke eventually finds himself challenged from all sides; even his own henchmen rally against him, and director Kihachi Okamoto stages confrontations that are as beautiful as they are graphically violent. As Ryunosuke descends into pure, bloodthirsty insanity, Sword of Doom ends with a freeze-frame that's unforgettably intense. --Jeff Shannon
I love that trailer!
One question tho.. Amazon states most impressive swordplay in the history of samurai epics yet in the trailer there are only 1-slicers...
I look forward to seeing it someday :)
Well, I can't say how it compares to other swordplay movies, as I'm not good at recognizing the bad or the good, but promo writers always exaggerate anyhow.