Gozu Tennō

The disease-spirits in this collection — the crone who asks for sweet sake at your door, the pox god you paint red, the ones you appease and misdirect — have a king, and he is exactly as contradictory as the rest of them.

Gozu Tennō, the Ox-Headed Heavenly King, is both the cause of epidemics and the protection against them.

That isn't a muddle. It's the operating principle of the entire disease wing. If plague is something that arrives with a will behind it, then the being that sends it is the only being who can be asked not to. You don't fight him. You get on terms.

He arrives in Japan as an imported Buddhist deity and, by the Kamakura period, merges with Susanoo — the native storm god, the one who wrecked his sister's fields and killed the eight-headed serpent. The merger may go back to an epidemic in 877.

The knock at the door

The story that carries him is about a traveller looking for a place to stay.

A god is on the road in disguise, and he asks two brothers for lodging.

The rich brother refuses. He has room and he says no.

The poor brother, Somin Shōrai, takes him in and shares what little he has.

And the reward is epidemiological. The god gives Somin Shōrai's household a means of surviving every future plague: wear a ring woven of reeds, and declare yourself a descendant of Somin Shōrai.

That formula is not a museum piece. It is still printed on talismans across Japan, and people still walk through the great woven reed rings set up at shrine gates in summer, stepping through to purify themselves for the season ahead. When you pass through one, you are invoking a poor man's hospitality to a stranger, about a thousand years after the fact.

The two doors

Now put this next to the amazake-babaa, and something clever comes into focus.

At her door, an old woman asks for a drink in the night, and answering her lets the smallpox in. The rule is: do not engage the unknown visitor.

At Somin Shōrai's door, a stranger asks for lodging, and refusing him damns your household forever. The rule is: never turn the visitor away.

Directly opposite instructions, in the same tradition, about the same situation.

Which is not a contradiction — it's the whole curriculum. Folk belief isn't teaching you a rule about doors. It's teaching you to tell which visitor you have, and it's honest that the stakes run both ways: the wrong refusal is as fatal as the wrong welcome.

You've seen his festival

Kyoto's Gion Matsuri is one of the largest and most famous festivals on earth. Vast wheeled floats, hauled through the streets in July, photographed by everybody who has ever visited Japan in summer.

It is a plague-prevention ritual, and it always has been. It grew out of the Gion faith centred on this deity, at what's now Yasaka Shrine — a response to epidemic, performed annually so that the epidemic does not come back.

Those floats are a public-health intervention that has been running for over a thousand years and has never stopped.

And then the state renamed him

One last thing, and it matters for how you read any Japanese deity.

During the Meiji period the government forcibly separated Buddhism from Shinto, and shrine registrations were rewritten. Gozu Tennō, a Buddhist-derived name, was purged — and the deity at Yasaka was officially re-identified as Susanoo.

By decree. A god's name changed on the paperwork.

The Gion faith tradition carried on regardless, because a festival a thousand years old does not particularly care what the register says. But it's a useful reminder that provenance discipline applies to gods as much as to monsters: what a shrine says it enshrines today may be the result of a nineteenth-century administrative decision.