Shōkera

Sekien draws it clinging to a roof — muscular, clawed — with its face at the skylight, looking down into the house.

At you.

And, as with so many of these, the picture came with no text at all.

But the story that grew around it is the interesting part

To follow it you need to know about Kōshin.

Kōshin belief holds that there are three worms — the *sanshi*, the "Three Corpses" — living inside every human body.

And on Kōshin nights, which come round every sixty days, those worms leave you while you sleep and ascend to heaven to report your sins.

The consequence is straightforward: whatever they report gets deducted from your allotted lifespan.

And the countermeasure is equally straightforward.

You stay awake.

If you don't sleep, they can't leave. So you hold a vigil — and vigil, in practice, means a party. Food, drink, conversation, games, and a group of neighbours keeping each other conscious until dawn.

This is thoroughly documented, it was enormously popular, and Kōshin towers — stone markers commemorating the vigils — still stand all over Japan. You walk past them constantly in rural areas.

And the shōkera is cast as the invigilator

The later interpretation makes the shōkera the monitor of the vigil — watching through the skylight to see whether the household is observing Kōshin night properly, and punishing the ones who fell asleep.

And one text, the Kōshinden, goes further: it reads the shōkera as the Three Corpses themselves, personified.

Which would mean the thing on your roof isn't checking on you from outside.

It came out of you, and it's on its way to file the report, and it's looking back in through the window on the way up.

Now let me separate the layers, because they aren't the same age

The vigil practice is real, old, and thoroughly documented. Genuine popular religion, with physical monuments, running for centuries.

The picture is real, old, and completely silent. Sekien's plate and the 1737 scroll before it, with no caption.

The splice between them is largely Shōwa-era scholarship — a modern reading that connected a mute picture to a well-attested practice.

That's a plausible splice and I'd guess it's roughly right. But it is a modern argument, not an Edo belief, and the distinction matters.

Except there's a complication, and it strengthens the case

Here's the detail that upgrades this from a guess.

The name shōkera appears inside the practice's own liturgy.

It turns up in Kōshin-night observances — including a protective incantation that names it.

So the word genuinely belongs to the vigil. People saying the words on Kōshin night were saying "shōkera."

What remains modern is the connection between that word and Sekien's picture.

Which is a much better position than most mute plates end up in: the term is attested in the ritual, and the only open question is whether the artist was drawing that thing or something else that happened to share a name.

The details, honestly assessed

The name glosses as "mole cricket spirit" — a real insect, one that lives underground, which fits a worm that lives inside you.

The identification with the sanshi is refined in the record to "possibly the middle worm, with beast features."

And the version with three claws — three corpses, three claws — is later text.

That rhyme is a bit too tidy. Three worms, three claws is exactly the sort of correspondence that gets noticed later and then read backwards into the picture.

I'd treat it as a modern rhyme, and I'd keep the genuinely unsettling part, which needs no help:

Something is on your roof, at night, on a specific date, watching to see whether you have gone to sleep.