Hetu & Luoshu

The River Chart and Luo Writing

A dragon-horse bore the Hetu from the Yellow River and a spirit tortoise bore the Luoshu from the Luo River; from them Fuxi drew the Eight Trigrams and Yu mapped the Nine Provinces.

The Book of Changes says: "The River produced the Chart, the Luo produced the Writing, and the sages took them as models." Fuxi formed the Eight Trigrams from the Hetu; Yu the Great based the Hongfan and the division into Nine Provinces on the Luoshu, whose numbers and directions shaped calendars, geomancy and divination — the "wordless scriptures" of Chinese civilization.