"GI Samurai" sees Sonny Chiba and some other guys get transported back to civil war stricken feudal Japan for no particular reason, and much carnage ensues. It's a rather over the top essay of sword vs. machine gun that ultimately yields some interesting results.
The plot essentially runs along the rails that you might expect from the title; initial fish-out-the-water antics ("what is this flying metal box?" etc etc), "aren't we better off here" discussions and ultimately a huge battle. The latter is proof that the film doesn't take itself seriously at all, the carnage taking up most of the second half as samurai army battles Chiba's platoon; a face off one would fully expect from the title but it still manages to overwhelm with its inventiveness and extravagance. It's certainly one of the most unique battle sequences of its time and doesn't drag despite its extended length.
Chiba gives a gruff performance as Iba, initially a good leader but someone who finally finds himself questioning his own morals as the situation slowly has an effect on him. This is certainly one of his better vehicles from his terrific CV. By the final act the two worlds have had such an effect on each other you have to wonder if it was a bit of nihilism on the part of the writers, as they seem to be asking "weren't we better off back then?'. But this is maybe reading a bit much into was can generally be described as a hugely entertaining two hours of (almost) non stop action.