The origins of the He Tu diagram according to Chinese mythology is that Fu Xi came across a dragon horse at the yellow river.
On the back of this majestic animal were black and white dots that formed a pattern that can be deciphered into a configuration of numbers.
It was then known as the He Tu diagram or river map chart.
This was the basis of how the river map was created.
Over time, additional context such as directions and elements were found to fit seamlessly into the concepts.
While the He Tu is known by feng shui masters, the application of it is seldom used. Even in practice, it is usually applied with the early heaven arrangement of trigrams.
Modern practice of feng shui uses the Luo Shu diagram extensively instead.
However, feng shui experts can sometimes refer to the river map when assessing a site because they possess the knowledge and expertise to identify when the he tu is relevant.
Before we go on, just be mindful that you might be a little confuse here as He Tu is markedly different from what we are used to with elemental representations and directions.
There are 10 numbers in the river map from 1 to 10.
They occupy the 4 cardinal directions and the center, each location made up of 2 numbers.
Odd numbers represent yang characteristics while even numbers are associated with yin characteristics.
The numbers that are paired off all have a difference of 5, which is no coincidence as 5 is a number of neutrality.
The plotting of numbers into the He Tu chart follows a clockwise sequence incorporating the elemental cycle of birth.
It must be noted that while modern feng shui tend to use the Luo Shu, the He Tu configuration is the basis of how some heavenly stem combinations are derived.
This has essential applications in flying star and bazi analysis.