This one is Gosha's first directorial attempt, and what a debut! Though some of the performances are occasionally a bit overwrought, there are also many instances where Gosha reveals his sense of the camera.
Of course, there are Gosha's typical studied camera angles and compositions (you see some interesting "moving camera" work, which significantly predates the attempts of "pioneering" US directors). However, "Sanbiki no samurai" also showcases Gosha's ability to tell a story through facial expressions, rather than simply relying upon dialogue.
This is all film-school wankery. The bottom line is that "Sanbiki" is a gripping chambara flick, with a solid morality tale disguised as a cynical amorality tale. (Note that a common theme through many Japanese "chambara" is that of cynical ex-samurai who ultimately decides to risk life and limb for some hopeless but noble "little guy" cause.)
This theme was repeatedly, um, emulated by the likes of Sergio Leone with his spaghetti westerns. However, my point is that such tales are just plain entertaining. The three actors playing the samurai also turn in great performances.
Viewers new to Hideo Gosha may wish to start with "Goyokin" or "Hitokiri" (a/k/a "Tenchu"), but if you've seen those two already (or if they're already checked out), then this is still a definite movie to catch!