Musashi: The Dream of the Last Samurai is an unusual film to watch. Rather than a dramatization of its subject's life, it is in fact a straightforward documentary. Not that documentaries in anime style are completely unheard of – Gainax had a stab at the format in the 80s and 90s with titles like Money Wars and Otaku no Video, and more recently there was the Japanese government funded Megume about a young girl that was kidnapped by North Korean spies in the 1970s. But Musashi goes a stage further by having very little dramatization at all, in favour of being presented as a lecture.

What makes this instantly interesting is that it is a lecture written by legendary anime director Mamoru Oshii (Ghost in the Shell, The Sky Crawlers) , a creator famed for his – at times morbid and extremely analytical – obsession with war and military combat. Add to that the fact that the movie was directed by Oshii's long time collaborator Mizuho Nishikubo, the film's production staff alone make Musashi an instantly appealing proposition to a legion of dedicated anime fans.

Still, this is a very unique and unusual film. Firstly, it is a lecture given by a simply designed, strange looking cartoonish CGI professor. In fact, the lecturer looks decidedly like a Wii avatar (of Oshii himself, perhaps), as does his mute female assistant, that seems to serve no purpose but to to provide some – slightly annoying – light slapstick comedy relief by flailing about in the background.

If that sounds a little bizarre... well, it is. Especially when contrasted with the variety of different visual styles the movie also deploys, in addition to some live action footage shot on real historical locations. There are some animated sequences depicting some of Musashi's key battles and duels, and they're gorgeous, having been made in the kind of polished, dark style that is synonymous with much of Oshii and Production I.G's work. In fact, they're so impressive to watch that it's hard to not wish that the entire film were animated that way; not only is the animation fantastic, but it serves as a far more effective way of delivering the lecture. Sadly, it's the latter that seems to dominate screen time.

Similarly strange and distracting is the use of music. While Oshii fans might be expecting another fantastic Kenji Kawai soundtrack, instead the audience is presented with an odd mix of inappropriate classical music and traditional Japanese folk songs, with the lyrics of the latter at times actually forming part of the lecture. While this makes perfect sense in theory, with some of the music fitting the era that's being examined, in practice the odd mix becomes jarring for the viewer. Although nowhere near as bizarre as the CGI lecturer, it seems to add to Musashi's fundamental problem: that its constant swapping of styles and experimenting with different formats tends to leave the audience distracted rather than stimulated. The bizarre score certainly doesn't help, and as a total package, the film is a bewildering experience.

Which perhaps sums up Musashi's problems, at least from a western perspective. The subject matter, while probably quite familiar to most Japanese viewers, is going to be new territory for many English language audiences. Ironically, while the decision to use a shifting range of presentation styles seems to have been made to try to liven up a subject that's perhaps over-familiar to Japanese viewers, for those new to the history it just ends up being a little too distracting. Then again, it's more than a little obvious that Musashi wasn't made for an international audience; rather, this feels like it was produced for the Japanese equivalent of the History channel, or as an educational aide for students. It's easy to imagine this film being shown in a Japanese high school history class.

Not that watching Musashi – The Dream of the Last Samurai is a completely unrewarding experience; far from it. If you have even the slightest passing interest in Japanese history and philosophy, samurai culture or even military theory and strategy in general, it's worth checking out. Oshii's theory – that Musashi developed his dual sword style because he dreamed of becoming part of the horse riding cavalry elite - seems solid, and becomes even more interesting when he expands his view to examine the place of horses in combat in European armies, along with the role of the aristocracy and even the development of the modern tank. Similarly, this is essential viewing for die hard Oshii-fanatics, who'll be fascinated to hear his views on military development, and will probably recognise how the film's experimental approach has developed from his equally odd animated Patlabor lectures, Minipato. It's also worth a look if you have any interest at all in anime that breaks away from the mould, and tries to do something very different – something that Musashi – The Dream of the Last Samurai certainly aims for, but with wildly mixed levels of success.