There was a saying in the ancient martial arts family: "Those who can paint shadows will win the world."
Aroused different opinions...
No one knows what the shadow is.
Some people said: It is a knife.
Some people say: It is a sword.
Some people say: It is the secret book of the Li family.
Rather than weapons, everyone would rather believe: it's a secret book...
…Indicates that the copywriter is incompetent