70-30 Rule

In the west, most people are familiar with the 80–20 rule also known as The Pareto principle, which states that, for many events, roughly 80% of the effects come from 20% of the causes.
In china what constitutes natural order more closely approximates a rule of seventy. In matters of food; your pantry should be 70% full, your rice bowl 70% filled with a serving of 70% whole grain/vegetable and 30% meat. Eat to 70% of your stomach’s capacity. Leaving the pantry, bowl or stomach (likened to a cooking pot) 30% empty allows proper circulation of chi or energy. Overfilling could cause chi blockage, blocks or stagnation are pathological conditions according to Traditional Chinese Medicine.
Lau Tzu said the people should have their minds emptied and their bellies full. Some social scholars equate this with Lau’s desire to keep the masses ignorant and provide “government cheese” for welfare and dependence on the state. Professor Cheng Man Ching corrected this misunderstanding when he said the Lau’s true meaning meant to empty their minds through meditation and fill their bellies with Chi! The first interpretation enslaves while the second empowers.
The summation of the above is preventive medicine at its finest for in addition to dietary, environmental influences such as kitchen space, utensils and body constitution and philosophy This is preventive medicine at its finest because in addition to dietary, it considers meditation, chi development, environmental influences (feng shui) including kitchen space, utensils (even
a bowl must be empty to be useful), body constitution and philosophy as part of healing.
In tai chi the seventy percent rules equally applies. In the act of shaping your postures or stretching your muscles do strive for about 70% of your natural capacity, (the dragon doesn’t excessed its limits, thus forestalling entropy and chaos). This means holding 30% in reserve. 70/30 being more balanced than say 50/50. Try achieving anything when two opposing parties equally share half the power.
As Lao Tzu said, to reach too far is to exceed one’s grasp and to step too long restricts stride. (I’m paraphrasing) both these overextensions lead to a condition called double weighting in tai chi. A situation where body weight is distributed equally on both feet simultaneously, immobilizing, impeding and hindering movement. Step only 70% of your stride length.
Remember 70% is the maximum, else too much strain and energy loss may occur with unwanted consequences including injuries. This certainly isn’t the “balls to the wall” athleticism of today. But it is patent and has its merits, like injury prevention and consistent skill development over time.
Have you wondered why 70% of the body weight is on the forward foot while in the archer (bow stance) stance, as in ward off left or right?
It’s simple, the lower part of the body is about 60% body weight when considering the hips and legs, the upper body or torso weights about 40%.
When the two legs are divided each leg/hip is around 30% each (60% divided by 2). When standing on both feet as in the opening of tai chi, each foot bares its own weigh - 30% plus half the upper body weigh 20% or 50% of total bodyweight is carried on each leg.
But when one leg is extended as in the forward bow and arrow stance that leg now supports its own 30% plus the 40% torso weight falls into that leg as well.
Hence 70% of the weight is on the forward leg while in the archer stance! While the rear leg supports its own weight of 30%