This is the tenth of 26 films to star Shintarô Katsu as Zatoichi.
In the film they refer to a character receiving a hook and being promoted to constable. This refers to the Japanese jitte, which translated means 'ten hands', and was a weapon carried by police in the Edo Period of Japan.
While Zatoichi is repeatedly referred to as a masseur in the English subtitles, the Japanese term Anma would be more correct. Anma was both the term used for the practice and the generally nomadic practitioner of Japanese massage. In fact, edicts were passed so that massage was solely a vocation for the blind, forbidden to be learned by any with sight.
This film is part of the jidai-geki genre, which translates to 'period drama'. It is also a 'chanbara' (sword fighting) film.
Zatoichi's katana is a shikomizue. This is a sword which is concealed within a wooden cane, thus the cane itself is both handle and scabbard.