The Sanka: Japan's Unregistered Mountain People Between History and Legend

People without family registers once built temporary shelters by rivers and moved from mountain to mountain—or so accounts of the ‘Sanka’ from around Japan suggest. Yet almost no official records remain, and even if such people existed, the nature of the group is still unclear. The video untangles, in sequence, the traditions and inventions that entered this gap.

It first presents records by ethnologists and fieldworkers who said they encountered people without family registers in the mountains. Works such as Tsuneichi Miyamoto's *The Forgotten Japanese* are cited, along with the possibility that 17th-century documents recorded similar people.

‘Sanka’ was not their own name but a term with discriminatory implications used by police and officials from the Meiji era onward. Names differed by region. They were said to make temporary riverside homes called seburi and move every few days or months while making and repairing winnowing baskets.

After World War II, family-registration and education systems made a mobile life harder to maintain. The video introduces the theory that they settled and blended into wider society: perhaps they did not disappear so much as the boundary ceased to be visible.

Beginning in Ikebukuro, Tokyo, in 1926, the so-called ‘preaching robber’ became known for lecturing victims for hours about locks and watchdogs after taking their money. His agile escapes fueled rumors that he was Sanka, but the presenters say no firm evidence existed and prejudice against an unidentified mobile population came first.

In 1929, fingerprints identified a culprit who was not Sanka. The video treats the episode—in which an inexplicable crime was projected onto a scarcely documented, little-known group—as revealing how the Sanka were viewed.

The story then moves to a legend that the Sanka descended from the Kunitsukami or Izumo forces who refused to submit to the Yamato state after the transfer of the land and entered the mountains. A theory that they were descendants of Jomon people with little continental influence follows, but the video explicitly says neither is supported.

It also lists theories that Toyotomi Hideyoshi came from the Sanka, that they originated the ninja, and that they were the same secret organization as Yatagarasu. Mountain travel skills and the supposed absence of registers and legal names expand the story, but the presenters distance themselves by calling these almost entirely unsupported urban legends.

The video says novels and embellishments by a journalist and author strongly influenced today's image of the Sanka, and that later invention entered accounts of Sanka writing and specialized tools. Even so, a warning-like line attributed to ethnologist Keisuke Akamatsu—that an underground organization might survive even after its members blended into society—casts a dark afterimage over the end.

The presenters conclude that the lack of settled information likely allowed the stories to acquire details and grow.