On the road blind swordsman Zatoichi (Shintarô Katsu) happens upon a dying man. He turns out to be a benevolent yakuza boss from a town called Tendo, killed in an ambush by a rival gang. Ichi arrives in Tendo alongside a friendly band of entertainers, including a gifted singer named Oharu (Kiyoko Suizenji), in town to perform at the state fair. They quickly discover that the unscrupulous new boss, Iwagoro (Tatsuo Endo) is out to extort as much money as he can from everyone. When Ichi, predictably, uses his super-senses to score a big pot at the local gambling den, vengeful yakuza thugs ambush him at a noodle shop. Naturally he makes short work of them but his lightning blade intrigues the only witness, Senzo (Eijiro Tono). It turns out Senzo was once apprentice to the blacksmith who forged Ichi's famous cane sword. He warns Ichi that the sword has reached the end of its 'lifespan', so his next battle could well be his last.
Whereupon Zatoichi realizes it might be time to finally quit this sword-fighting lark and settle down with a nice, quiet job; though we all know that won't last. Interestingly Zatoichi's Cane Sword, the fifteenth entry in Japan's most popular chanbara series, spins an entire story out of what would serve as a minor plot point in the later Zatoichi Meets Yojimbo (1969), namely Ichi's cane sword being close to breaking. Much like the Godzilla films the Zatoichi series adopted a ritualistic story-structure recycling familiar motifs. Fans knew what would happen (Ichi would score big at the gambling den, defend the honour of a young maiden, fight off a dozen opponents single-handed then close the film squaring off against a super-skilled rival), but not how. Despite the formulaic nature of the long-running series producer-star Shintarô Katsu and his production team consistently reshaped familiar ingredients into stories that were compelling, occasionally dynamic and moving. In that regard many fans rate Zatoichi's Cane Sword among the series' finest. Yet despite fairly well sustained level of tension, some nuanced relationships along with a dose of quirky comedy, the film is actually among the more meandering and inconsistent entries.
The plot unfolds in a highly circuitous fashion and veers off on frustrating tangents, spotlighting characters who have no bearing on the story. As well as an accomplished dramatic actor Shintarô Katsu was an all-round entertainer, performing comedy skits, playing traditional Japanese musical instruments and crooning the occasional song. As such he made the Zatoichi series a showcase for popular showbiz acts. Hence Zatoichi's Cane Sword features a musical sequence early on where the personable Haru performs a lovely song with a country flavour. Yet having established Haru as an affable co-star, the film sidelines her for no discernible reason. The bulk of the plot centres around yet another young damsel named Oshizu (Shiho Fujimura) whom Ichi encounters when he tries to lay low at the local inn in his other occupation as a masseuse. Oshizu happens to be the adopted daughter of the dead yakuza boss Ichi found in the opening scene. Torn between filial loyalty and personal desire she fends off the advances of an adoring young man named Seikichi (Yoshihiko Aoyama) whilst attempting to help her adopted brother Shinnosuke (Junichiro Yamashita) seek revenge. A large chunk of the plot reduces Ichi to a comedic supporting player in a Shakespearean romance as he observes Oshizu sparring with the under-characterized Seikichi. He eventually advises Oshizu there is no point worrying her pretty little head about man's business like revenge, she ought to settle down and marry the nice young man. Which probably reflected attitudes of that time, to say nothing of the Sixties, but does not make it any less patronizing. Compounding matters, the cold, sharp-tongued Oshizu just is not all that interesting a character.
Eventually Boss Iwagoro turns the respectable inn into a brothel, beats up kindly Genbei (Ryuji Kita), then sets his sights on Oshizu. This spurs Zatoichi into action even though knowing his sword could break at any moment makes him more nervous and hesitant than usual. Aside from a brief though jarring dream sequence the plot underplays the weakness of Ichi's sword and involves a few too many villains (along with Boss Iwagoro the film features a corrupt policeman and a yakuza hitman) with nebulous motives. It is still not a bad film by any means. Performances are solid all round, not least the always compelling Shintarô Katsu (who gets to indulge show off his wacky comedic side by performing a song-and-dance number in a silly outfit), as is the cinematography (note the scene where Ichi's menacing silhouette looms over an unfortunate bad guy). Zatoichi's Cane Sword climaxes with a spectacular sword fight wherein the villains exhibit more fiendish ingenuity than usual while Ichi hides inside a giant rolling barrel (a sequence Katsu later re-staged in Zatoichi the Blind Swordsman (1989)). There is also an amusing gag involving a friendly rickshaw driver that pokes gentle fun at Ichi's traditional final face-off with a deadly rival. However, despite laudable moments, this Zatoichi adventure is ultimately less than the sum of its parts.