Two figures painted on a doorway, spear in hand, keeping watch through the night so nothing evil may cross the threshold — the record files this custom under the plain heading "The Door-gods". Its witness is Werner's Myths & Legends of China (a compilation of Chinese myth published in 1922), which sets the origin on Mount Tu Shuo, in the Eastern Sea, where grew "a peach-tree of fabulous size". Its lowest branches bent to form the "Door of the Devils" — the text glosses the term _kuei_ — through which spirits passed in and out, and two guardians, "Shên Shu (or Shu Yü) and Yü Lü," bound the wrongdoers, who were "given over to be devoured" by tigers. When Emperor Huang Ti heard of it, he had the pair "painted on peach-wood tablets and hung above the doors" to "keep off evil spirits"; from that came the paper images later "pasted on the doors," the two "armed with bows, arrows, spears," "Shên Shu on the left," "Yü Lü on the right."

A second legend overwrites the first. Two ministers of "the Emperor T'ai Tsung of the T'ang dynasty," "Ch'in Shu-pao and Hu Ching-tê", stood "fully armed" outside their sick lord's door while demons tormented him at night, and he slept in peace. Unwilling to keep them from their rest, the emperor had them "paint their portraits" "in full martial array" and paste those on the palace doors instead — and the painted men warded as well as the living ones. Pictures of these _mên shên_ (door-gods), the witness closes, "renewed at the New Year," hang "on almost every door in China."

The shelf here is narrow — a single Chinese witness, no second tradition wired beside it — yet that witness is unusually full, carrying the custom from peach-wood plaque to New-Year paper and from ancient spirit-guardians to two remembered courtiers. When a guardian is only a picture of a guardian, what is it that the image is trusted to do?