Great Yu's flood-control works

Great Yu’s flood-control works enter the book not as a narrated campaign but as the circumstance surrounding a legendary revelation: while Yu was draining floodwaters, a tortoise emerged from the Luo River and displayed a diagram that suggested the Great Plan. The account links the management of a physical crisis to the making of a foundational political and divinatory scheme, while the author treats the story as part of a later, supernatural explanation for the diagrams rather than as proof of their actual origin.

The Flood and the Revelation

In discussing competing accounts of how the lineal figures were formed, the author describes the tradition that a tortoise came out of the Luo River and showed its markings to Great Yu during his celebrated work of draining the flood. The setting matters: the diagram appears amid an undertaking to control waters that threatened the land, and its recipient is a sage associated with that work. In this telling, flood control and cosmological knowledge meet in a single episode.

The diagram was said to suggest the Great Plan, an influential and mysterious document in the Book of Documents. The author, following Gaubil’s description, characterizes that work as treating physics, astrology, divination, morals, politics, and religion, and as serving as a model for governing the kingdom. The revelation therefore carries an expansive claim: a pattern disclosed during the ordering of waters becomes a guide to the ordering of public and moral life.

The Diagram’s Place in the Book’s Account

The flood-control episode belongs to the book’s discussion of the Ho map and the Lo writing, two diagrams associated with supernatural origins for the trigrams. The author says that the Lo writing was of the same general kind as the Ho map, but appeared on the back of a tortoise from the Luo River. He then notes that the received representation of the writing is a scheme, while warning that its present form may not reproduce the version known in the Zhou dynasty.

This qualification keeps the story’s significance distinct from its historical certainty. The author presents the tortoise’s appearance and the diagram’s revelation as the tradition’s explanation, not as a firmly established account of how the figures originated. Elsewhere, he favors a more direct explanation based on manipulating whole and divided lines, and suggests that the supernatural scheme was intended to lend the trigrams religious veneration. The Yu episode thus illuminates the authority later attached to the diagrams even as the author questions the tradition’s account of their beginnings.

Divination and Political Order

The episode also sits within a longer history of divinatory practice. The author points to references to divination by tortoise shell and stalks in early books of the Book of Documents, including the Great Plan’s instruction that doubts be examined through those means. In this context, the tortoise’s appearance is not an isolated marvel: it gives a legendary origin to a method by which people sought guidance when confronting uncertainty.

The Great Plan’s range—from divination to government—makes the connection especially pointed. Yu’s task was to drain the flood; the diagram disclosed amid that work becomes associated with a scheme for governing the kingdom. The account therefore binds material intervention and political order to a shared image of bringing disorder into intelligible form. That interpretive significance belongs to the tradition as the author recounts it; the passage does not describe the practical details or outcome of Yu’s flood-control work.

A Traditional Origin, Not the Author’s Preferred One

The author explicitly sets this account beside a second explanation of the figures, which he considers true: once whole and divided lines are posited, they can be combined to produce the lineal figures. He cannot identify who devised the map-based explanation and doubts that the scheme as currently drawn is the correct one for the Zhou dynasty. The Great Yu story consequently functions as evidence of how a supernatural character was conferred on the diagrams, rather than as the author’s own explanation of their formation.

That distinction also marks the limits of what the episode establishes. It associates Yu’s flood-draining work with a tortoise, the Luo River, and the diagram that suggested the Great Plan; it does not supply a chronology for the work or recount its stages. Its force in the book is chiefly intellectual and historical: a legend about flood control helps explain how divinatory signs could be connected to a comprehensive vision of knowledge and rule.