Is Master Yan Xin's spontaneous kung fu a possession kung fu method

No. Since the internal exercise of Yan Xin qigong relies mainly on visualization and breathing, the effect produced is extremely limited, and it still relies mainly on external forces, and if the external forces do not work, the effect is not ideal, which is also being withdrawn by the external forces in the later stage of the widespread support for this gong method, the majority of practitioners of Yan Xin qigong results are not ideal. Therefore, Yan Xin Qigong is still essentially a dharma that relies mainly on external forces.