This time, he was developing the Heaven-Covering Hand by using the Skin Appearance Sutra as his guide, following a new line of thought.
He did this for no other reason than to thoroughly understand the Skin Appearance Sutra.
For example, if developing the Heaven-Covering Hand was like adding the numbers from one to a hundred, then Xu Yi's original method was to add them all by brute force, while the Skin Appearance Sutra provided a specific way to solve the problem.
The end result was the same, but the process was different. What Xu Yi wanted was to master that process—and, in turn, learn how to use it to build techniques based on the Skin Appearance Sutra.
Xu Yi had not started turning mathematical techniques into cultivation arts only after meeting Cao Da and the others.
In fact, even back in the Body Tempering Realm, the Return to Origin Steps and Hidden Edge Style he had mastered were both examples of mathematical techniques evolving into cultivation arts.
It was just that, as his cultivation advanced, the arts he had learned in the early, lower realms were no longer useful.
Of course, that did not mean there was anything wrong with those arts themselves. They were still perfectly suitable for using as a reference to verify the Skin Appearance Sutra.
And so Xu Yi kept using the mathematical arts he had mastered in the past as a guide to the Skin Appearance Sutra. Each time he used the sutra's methods to recreate an old art, he gained a new insight.
The process was like opening up blocked meridians. If the Skin Appearance Sutra was a vast net covered in nodes, then Xu Yi's strategy of using it to recreate his old arts was a way of clearing the pathways.
Each old