He had an intuition
"Keep this and hide it in your space ring. Only take it out when you're cultivating. Also, you must go into seclusion every time you cultivate. Don't let anyone know about this." After the Jing family head and the others left, Ling Chuxi took out a piece of dark green heaven and earth bamboo and secretly handed it to Jing Ziyu.
This set of cultivation technique could only be cultivated with the help of a rare chaos treasure. This was also one of the reasons why Ling Chuxi was willing to be open about the cultivation technique. Without a rare chaos treasure, no matter how heaven-defying a genius was, he could not even dream of successfully cultivating it. As for how much master Jing and the others could cultivate if they wanted to learn, that was not something Ling Chuxi had to worry about.