A girdle here is the key that knocks at the door of the sea. In the 1922 collection Myths & Legends of China, a graduate named Liu I, riding home after failing his examination, meets a "young woman tending goats by the roadside" who tells him she is "the youngest daughter of the Dragonking of the Tung-t'ing Lake". Married away and then, "misled by the slanders of the servants", cast off by her husband, she begs him to carry a letter to her father. North of the lake, she says, stands a great orange-tree "called by the natives Protector of the Soil"; there he must "Strike it three times with your girdle", and someone will come.

Months later the graduate finds the tree and "struck it three times, whereupon a warrior arose from the lake". The warrior parts the waters and leads him down to the Dragon-king's palace, where the letter is delivered and the daughter, in the end, restored to her people. What is magic in the belt is understated almost to vanishing: it is simply a man's own girdle, lifted from his waist and used as a summoning-rod against the bark of a tree.

That understatement is the honest measure of the shelf here. Only the Chinese witness is wired to served text, and even it grants the girdle its power in a single stroke; the girdle of Sir Gawayne and the Green Knight, and the Irish and Tuamotuan belts filed alongside it, wait unread. Still the gesture is exact and strange — three knocks, and the sea opens a door. What is it about a thing worn close to the body that a story trusts it, over any staff or sword, to call the drowned world up?