Merging spirit and soul is simple. Forging one's physical body and qi and blood in a single crucible isn't difficult either. But to merge all four? The difficulty is on a whole other level.
Spirit and soul; body and qi and blood.
It wasn't as if these four concepts were completely unrelated.
In fact, given that they all combined to form the "human body," they were inherently connected.
But to unify all four—one could sense the difficulty just by thinking about it.
Li Chang'an had pioneered the use of acupoints through the Martial Scripture.
Each time he refined an acupoint, his strength would take a qualitative leap.
But this was merely building on the work of others, and the increase in strength was still largely confined to the physical body. Only a very small number of acupoints could affect his soul and spirit.
