《河圖》

This passage explains the numerical arrangement principles of the ancient Hetu (River Chart), a legendary auspicious pattern said to have emerged from the Yellow River:

The original numerical layout of the Hetu contains forty positions distributed among the four cardinal directions (east, south, west, north) and four intermediate directions (southeast, southwest, northwest, northeast). Using Tianwu (Heaven Five, where the number 5 represents heaven) and Dishi (Earth Ten, where 10 represents earth) as empty core positions, these two numbers govern the cyclical movement of the remaining forty numbers. Thus the combined sum of heaven and earth's numbers totals fifty-five.

Earlier versions of the Hetu were altered into square configurations, with the Tianwu number materialized at the center, rendering the diagram unusable for calculations. Now presented for the first time in its circular form, the original mystical properties are verified. Careful observers examining the diagram will naturally comprehend its profundity through subsequent illustrations.

(Supplementary note: The "Heaven Five-Earth Ten" concept referenced here holds significance in ancient numerology - 5 represents the ultimate yang number while 10 represents the ultimate yin number, together symbolizing the harmonious interaction of heaven and earth. The circular structure better aligns with the ancient cosmological view of "round heaven and square earth.")