A Zanbato (literally "horse-slaying sword" or "horse-chopping saber") is an especially large type of Japanese sword, the historical use of which is disputed. The sword closely resembles the nodachi or odachi, however it differs from the nodachi by having a ricasso of approximately 12 to 18 inches (460 mm). This lends more to the theory of the sword having a practical use in feudal Japan. The increased length of the blade, along with the extra grip, would give it dual use both as a sword and as a polearm for attacking advancing cavalry. This style of zanbato sword can be found for sale in rural tourist shops and stands in Kyoto and Nara prefectures of Japan. This sword may have been inspired by the Chinese zhan ma dao as both were said to have been used for killing the horse and rider in one swing. It is likely that the zanbato is actually a mis-construction of the zhǎn mǎ dāo, poorly drawn or translated by Japanese travellers who witnessed the weapon being used during battle.
Such extremely long and curved zabatao swords did exist, and were solely used for ceremonial purposes. Experienced smiths often took upon themselves to prove their talent by creating these so-called "zanbato" as a way to challenge themselves. This led to the extremely long blades often seen in ancient depictions, some of which were so long (over a dozen feet long) that they could hardly be mistaken for something other than display pieces.
An incredibly large sword forged during the Edo period of Japanese history. Although it was originally meant to take down a horse and its rider in one swing, the weapon was so massive that it required at least two people to hold, much less wield. In the Japanese manga Rurouni Kenshin, fighting enthusiast Sagura Sanosuke, under the name 'Zanza', carried and fought with a zanbato, belying his incredible strength. Sanosuke's zanbato had no edge, due to its age; so although it was formally called a blade, it could only be used to smash and crush.
Hah! A zanbato? You'd have more luck finding one in a museum than in a shop anywhere in Japan!