Zatō is a title, the lowest of the four official ranks within the Tōdōza, the historical guild for blind men (thus, zato also designates a blind person in Japanese slang). Ichi is therefore properly called Zatō-no-Ichi ("Low-Ranking Blind Person Ichi", approximately), or Zatōichi for short.

As a blind warrior and using a wooden weapon instead of a Shinken, Seigen had to fight this way, because he couldn't see his opponent's blade and actual state. Seigen followed in his own death during some year in the 1590s.

His lightning-fast fighting skill is incredible, with his sword held in a reverse grip; this, combined with his unflappable steel-nerved wits in a fight, his keen ears, sense of smell and proprioception, all render him a formidable adversary.

In contrast to these films, Zatoichi is not a samurai himself but a kind of feudal version of a lumpen element who supplements his income by gambling. With his super-sensitive hearing, he can detect whether thrown dice come up odd or even.