This is the first book in the short-lived (only seven books in the series) western series Six Gun Samurai. As with most men's adventure series, the Six Gun Samurai series was written by several different authors (Mark Roberts, Patrick Andrews, and William Fieldhouse) and published under a universal pseudonym (Patrick Lee). As far as I can tell, this first entry in the series was actually penned by Patrick Andrews, who also published several western and adventure novels under his own name.
Six Gun Samurai is the origin story of "Tanaka" Tom Fletcher, a white man raised from childhood in Japan as a Samurai warrior, who returns to the American west in order to avenge his family who were massacred by Union soldiers. The book starts like your typical fish-out-of-water story, but soon becomes more focused on the action as Fletcher quickly learns to stop greeting people in Japanese and trades his kimono in for a denim vest.
Fletcher isn't the only one forced into a learning curve; Andrews isn't stingy with factual details about Fletcher's upbringing, and readers looking forward to a quick western take might not be prepared for the level of cultural education that takes up a fair amount of the book's narrative. Japanese and Spanish glossaries are even provided at the end of the book to help readers along with their comprehension homework.
But all study and no vengeance makes Tanaka Tom a dull samurai, so rest assured there is plenty of violence in between historical Japanese flashbacks and dream sequences. Fletcher's path to vengeance leads to Colonel Edward Hollister and his regiment of former soldier outlaws, who have been doing their fair share of looting and pillaging both during and after the war. Fletcher's run-ins with Hollister's gang members and other random marauders are always bloody affairs, with Fletcher's samurai swordplay bisecting torsos and severing limbs and heads alike, all in graphic detail.
The outlaws are just as brutal, although they make up for their lack of acrobatic vivisectionist skills with a sadistic inventiveness when it comes to torturing and (eventually) killing innocent prospectors and farmers. And let's not forget the rape. Oh yes, they rape a lot, especially children. In fact, child rape is used repeatedly throughout the book as a gauge of just how evil a bad guy is, although thankfully it isn't graphically described like the murder and torture.
Six Gun Samurai has everything one would want from a serial adventure western, including truly villainous bad guys, a unique loner hero, and hefty amounts of western flavor and violent gore, even if some western fans may find themselves skimming over a page or two of Japanese cultural refresher course.
On a side note, my paperback edition of Six Gun Samurai includes an excerpt from the first book in the western series Edge, which is another series written under a pseudonym, in this case Terry Harknett writing under the name of George G. Gilman.