C35 Yangyin technique

Wu Ji said that the cave Lu Feiyue was in, was only an ordinary cave, and the real problem lay with that Stone Door.

Earlier on, he had read of a technique called 'Yang Yin' in an ancient book on yin and yang.

This technique was specifically used for concealing one's identity. It could be considered a form of camouflage.

It was similar to a modern safe