The tenth product is the back product, which contains the introduction of hell, which is explained in Sodeji Kampo's book.
I don't recommend you to read the yin law heartlessly. I have seen a great Buddhist virtue before, and I don't recommend it, because it is not said by the Buddha. I haven't seen it, but I guess something in it is unfounded.
It should be noted here that basically the contents in the Buddhist scriptures are reliable, and so are the things in the theory, because the theory is based on the enlightenment of the scriptures or bodhisattvas, such as the author is a great bodhisattva. No other book in the world is so credible.