画図百鬼夜行（がずひゃっきやぎょう）
Gazu Hyakki Yagyō
Sekien's first yokai book, 1776: the illustrated night parade.
Three volumes, published in Edo in 1776, each creature on its own page with its name and nothing else. The first book is the most conservative of Sekien’s four: most of its subjects were already known from scrolls and tales, among them the kappa, the tengu, the snow woman, the fox fire, the nekomata dancing in a towel, the yamabiko in the mountains, the akaname licking a bathtub, the ushi-oni on the shore, the tree spirit kodama standing beside its pine.
Because it is first, it is the book most often meant when someone says a yokai “is in Sekien.” The three sequels, in 1779, 1781 and 1784, add commentary, invention and the tool spirits.
Related yokai
Akaname
垢嘗（あかなめ）
Sekien drew a crouching figure with a long tongue in a bathhouse in 1776 and called it the grime-licker. He wrote nothing else about it — and everything you have been told about dirty bathrooms was added afterwards.
Kodama
木霊（こだま）
Kodama can mean both a presence within an old tree and the echo that returns from a mountain — but Japanese tradition gives it no single fixed body.
Nekomata
猫又（ねこまた）
A 1931 Kagawa record describes an aging cat whose tail divides in two and that rises to dance on its hind legs.
Ushi-oni
牛鬼（うしおに）
Toriyama Sekien's 1776 print shows a bull-like head on a squat clawed body at the water's edge — and tells us nothing else about it.
Yanari
鳴屋（やなり）
Sekien's 1776 plate shows a crew of small oni at the posts and under the veranda of a wooden house, pushing at the timbers. He named them for the sound a house makes at night and wrote nothing else.
Tenome
手の目（てのめ）
Sekien's 1776 plate shows an elderly blind figure with a biwa on his back, holding out two palms, each with an open eye. He gave it a name and nothing more; the story of a murdered man hunting his killer came later.
Shōkera
しょうけら
Sekien drew Shōkera in 1776 as a clawed, long-limbed figure clinging to a roof and peering in through the skylight. The plate gives a name and nothing else: no purpose, no victim, no reason it is looking.
Yamabiko
山彦（やまびこ）
The echo in a Japanese valley was heard as an answer before anyone drew the thing answering — and when painters finally gave it a body, they produced a small animal that is neither quite a dog nor quite a monkey.
Otoroshi
おとろし
Otoroshi appears in a 1737 scroll and in Sekien's 1776 book as a hunched, hairy creature — on top of a torii in Sekien's version. Neither says what it does. The story about it dropping on the impious was read out of the picture later.