Sansei

A mountain imp, somewhere between knee and waist height.

It stands on one leg — and the leg has its heel mounted backwards, so the toes point behind it.

It steals salt from mountain workers. It eats crabs and frogs. And it bothers travellers at night.

The countermeasure is the strangest in the tradition

You don't fight it. You don't carry a charm.

You say the name "Batsu."

Batsu — 魃 — is the drought demon. The scorching thing that dries up provinces; the same being Japan calls the hiderigami, the drought god.

Speak that name, and the sansei loses its power over you.

Which is genuinely peculiar when you sit with it. The ward against one monster is another monster's name — and a much worse one.

There's no priest here, no god, no sutra, no sacred object. You invoke a superior horror and the lesser one backs off.

The monsters of this tradition apparently observe a hierarchy, and know where they stand in it.

Why the backwards heel

Because footprints.

A creature with reversed feet leaves tracks pointing the wrong way. Follow them and you walk away from it. Look at the ground where it has been and the evidence says it went in the opposite direction.

Reversed feet turn up in a lot of the world's folklore for exactly this reason. It's the anatomy of something that cannot be tracked — which is a specific and practical fear for people whose work involves reading the ground.

The salt is the point

Salt theft is not a random detail.

Salt in pre-modern mountain Japan was a carried commodity. It didn't occur up there. It came up on somebody's back, along the salt roads, and it was expensive, and you needed it — for preserving, for cooking, for the animals.

A mountain worker's salt was one of the few genuinely valuable things they had with them.

So the sansei is a creature that takes the one high-value portable good in the camp. Not gold, not tools, not food generally. Salt.

That is a monster invented by people who had actually lost some.

And there's a truce clause

This is the detail that makes it feel real rather than literary.

Harm a sansei, and you sicken — or your house burns down.

Which sets up a workable arrangement, and it's stated as such: it takes your salt; you leave it alone; nobody escalates.

Mountain-labour détente. An annual tax paid in salt to something that lives up there, with a clearly understood penalty for non-compliance in either direction.

That's not a horror story. That's a working relationship with the terrain, expressed as a creature.

Where it came from, end to end

The sansei is one of the clearest import cases available, because every stage is visible.

Chinese texts — the Baopuzi, the Xuanzhongji, the Yongjiaji.

→ the Wakan Sansai Zue (1712), the great Japanese illustrated encyclopedia, which copied it in with its citations attached.

→ Sekien's plate (1779), which drew the reversed foot clearly.

→ and then, remarkably, into Iwate folk tradition — off the page and into the mountains of northern Japan, where people talked about it.

That last step is the interesting one. Most encyclopedia imports stay in books. This one got out, and became something the northern mountains told each other about.

It has colleagues

Japan's mountains keep issuing single-legged personnel.

There's a one-legged old man in Tosa. There's a one-eyed, one-legged monk on Mount Hiei. There's the one-legged smith-spirit of the Kii peninsula, hopping around the iron-working country.

And now the backwards heel.

Nobody has satisfactorily explained the pattern. The leading suggestion is occupational — that smelters and smiths in the mountains suffered characteristic injuries, to eyes and to legs, from the forge and the furnace.

Which would mean the mountain's one-legged, one-eyed population is a record of what the work did to the people who did it.