Folklore, retold
The story as it is told
A retelling, not a citation. What follows is the story as the most widely circulated popular accounts tell it — folklore encyclopedias, translations, and the versions that have travelled furthest. It is synthesized rather than keyed line by line to the dated primary texts, and popular versions drift from what those texts actually say. The cited, source-by-source record begins further down this page, and where the two disagree, the record wins.
Western Japan's growing roadman.
You meet something on the road at night, and it gains height as your gaze rises.
Shidaidaka — "progressively tall."
But the counter is different here
The Sado version of this monster is defeated by naming it — you look down and say I've seen through you, and it collapses.
Chūgoku's is optical.
> The creature grows taller as you look up — but becomes smaller when you look > down.
That's it. It's a dial, and your eyes are on it. Raise them, it grows. Lower them, it shrinks — all the way to nothing.
You don't defeat it. You wind it back down.
And some tellings go further
The extreme version prescribes looking at it between your own legs.
Bend forward, put your head down, and view the world upside-down through the gap.
That posture has a name — *matanozoki — and it turns up elsewhere in this tradition on the opposite side of the veil. It's a technique for seeing* things: bend over and look backwards between your legs and you can perceive spirits that are otherwise invisible. Sailors used it to check whether a distant boat was real.
Here, the same posture is used to delete one.
Same gesture. Once a lens, once an eraser. Which tells you it was never about what you see — it's about breaking the ordinary orientation of looking, and whatever that does to the mind is available in both directions.
The last bullet
This is my favourite detail in the entry, and it's an odd one.
In Gōtsu, in Shimane, hunters reserved their final bullet specifically for the shidaidaka.
Not for a bear. Not for a boar. For the thing that gets taller when you look at it.
A working professional habit, among men who counted their shot, with one round allocated to a monster.
And one of them fired it.
And the corpse was a nekomata — an aged cat, of the kind that grows a forked tail and stands up and starts commanding things.
Which pins two entirely separate doctrines together with one bullet: the gaze-inflation monster and the aged-animal monster turn out to be the same body.
And then it became a hill
Shimane also has the shidai-zaka — the slope that lengthens as you climb it.
No creature at all. Just a hill that keeps going.
And I think that's the quiet treasure of this entry, because of what it implies.
The same phenomenon, filed twice: once as a thing that exploits your gaze, and once as a terrain that exploits your legs.
Which is strong evidence that these yokai encode a real experience — the scale illusions of walking at night, when a shape at the edge of vision keeps resolving larger, and a slope you've climbed a hundred times seems not to end.
That experience can wear a body or a landform interchangeably, because the experience is the actual content. The monster is just one of the available costumes, and in Shimane they kept both.
Field guide
At a glance
- Behavior
- Grows taller as your gaze rises on the night road; feeds on your escalating attention.
- Powers
- Gaze-inflation — its size is your looking.
- Weaknesses
- Look down and it shrinks to nothing; the extreme cure is peering at it between your own legs.
- Oddities
- Gōtsu hunters reserved their last bullet for it; one fired shot revealed a nekomata under the giant.
- In Shimane it dissolves into topography — the shidai-zaka, a slope that lengthens as you climb.
Overview
Western Japan's growing roadman: meet it at night and it gains height as your gaze rises; the escape is optical — "the creature grows taller as you look up, but becomes smaller when you look down," shrinking to nothing as you lower your eyes; some tellings prescribe looking at it between your own legs [ja-shidaidaka]. Classified with mikoshi-nyūdō and taka-nyūdō [ja-shidaidaka]; Shimane and neighbors carry it.
The record
- The hunter's last bullet: Gōtsu (Shimane) hunters "reserved their final bullet specifically to confront shidaidaka" — and one who fired found the corpse was a nekomata [ja-shidaidaka]. The growing giant unmasked as the aged cat: two doctrines (gaze-inflation and seniority-transformation) pinned together by one bullet.
- The landscape drift: Shimane also has shidai-zaka — the slope that lengthens as you climb [ja-shidaidaka] — the yokai dissolving into topography: from a monster that exploits your gaze to a hill that exploits your legs.
The reading
With miage-nyūdō drafted the same day, the mikoshi family's two counter-measures now face each other: Sado's cure is rhetorical (name the trick), Chūgoku's is postural (drop your gaze; at the extreme, invert it through your legs — the matanozoki posture folklore elsewhere uses to see spirits, here used to delete one). Same monster, two theories of attention. The shidai-zaka drift is the entry's quiet treasure — the strongest evidence in the tradition that these yokai encode a real experience (night walking's scale illusions) which can wear a body or a landform interchangeably. And the last-bullet custom makes it the rare gaze-monster taken seriously enough for ballistics.
Two-track labeling
The image
Citations
The record
- [ja-shidaidaka]「次第高」ja.wikipedia via WebFetch (retrieved 2026-07-26), Tier C.modern reference Japanese Wikipedia's article on this subject, as retrieved in 2026 — often carries regional detail the English article lacks.All-source record
Where the evidence thins
Open questions
- Matanozoki (between-legs looking) as a toolkit entry — the posture appears on both sides of the veil (funayūrei sighting; here as cure).
- Taka-nyūdō/taka-bōzu variants (Shikoku) — family table row.