Strip away the monsters and Japanese folklore is a rulebook. Compiled here: every law the tradition actually teaches, each with its enforcing creature.
Don't look
The founding statute, from the top of the mythology down: Izanagi in Yomi; Toyotama-hime's birth-hut (break it and you found the imperial line anyway — at the cost of the sea's goodwill); the crane wife's weaving room; Kuzunoha's reflection; the yuki-onna's told secret; the wanyūdō's passing wheel ("look at your own child instead"). One glorious inversion: Kiyomori out-stared his dead and felt nothing — the rule breaks only for those past shame. And one tender reversal: the yamachichi's breath-theft is fatal only if unwitnessed — being watched over saves you. Even the basan plays fair: look, and it merely vanishes.
Don't answer
The modern wing's signature statute: aka-manto's red-or-blue (refuse the premise), kuchisake-onna's "am I pretty" (answer "average," offer candy, claim an appointment), the amazake-babaa at the door (silence and a cedar sprig), Kashima Reiko's leg question (the memorized password). The classical tradition punished looking; the modern one punishes engaging.
Though the classical wing had one too, and it is the deadliest rule on this page. On the Kiso river in storm, a voice calls from upstream — "Yaroka, yaroka", shall I give it? — and anyone who answers "if you're giving, hand it over" brings the flood down on the whole village (yaroka-mizu). The legend attaches to real disasters with dates: the Keian 3 (1650) flood that destroyed Kamihannya village with 3,000+ deaths, and the voice reported again in 1687 and 1873. Which makes it the tradition's most consequential piece of folk engineering: a rule that forbids answering strange sounds during storms is a rule that keeps people off the riverbank at surge time. The flood is polite; it asks; and one man's bravado signs for everybody.
Mind your manners
Courtesy is armor: "after you" dismisses the betobeto-san; a bow defeats the kappa (the spill); composure and a gift satisfy the okuri-inu; hospitality saved Somin Shōrai's line from plague forever. The hyōsube adds the exception that proves it: never return its laughter.
Feed the hungry
Cucumbers to the river (kappa); eggplant on a spear (hyōsube); azuki rice for the house-child (zashiki-warashi); rice-ball wages for the yamawaro — paid exactly as promised; the last grains left for the hidarugami; the segaki rite for the gaki, running since 657. Half the night parade is appeased with food, and the offerings map is a cuisine.
Keep the thresholds
The ofuda on the door (renewed yearly); the shimenawa's drawn line (first hung behind the sun itself); the mekago basket out-staring the one-eyed visitor; holly and sardine heads at setsubun; the cedar sprig; the carpenters' ink-line (yamawaro); the boulder at Yomi that started it all. Text and geometry — name the guardian, draw the border.
Name the thing
Say "mikoshita!" and the looming monk vanishes; say "abura-sashi" and the ubagabi flees her own crime's name; say "Batsu" and the sansei stands down before the drought demon's title; shout "TEN!" and Okiku finally rests. Naming is the tradition's oldest exorcism — which is, of course, what a bestiary is. It even reached a real courtroom: a hunter's mujina-or-tanuki defense went to the Daishin'in in 1925, folk taxonomy litigated as law.
And the one rule over all
Get home before the hour changes.
Assembly note: no new claims; sequencing of drafted, cited material only.