Later, Fujiwara's family designed to attack his great companion Jin Mao in the name of imperial edict when going out hunting, and said that Jin Mao's followers could leave safely as long as they laid down their weapons, and if they could capture or kill Jin Mao alive, they would get a reward. None of the more than 70 "servants" of Jin Mao surrendered or defected, and all died under the leadership of Jin Mao. This spirit was rewarded by everyone, including Fujiwara, and Chongan personally set up a monument for them.
Since then, the square beard has become a "symbol" of many warriors, expressing their loyalty and fortitude. This is the origin of their beards. Generally, in Guo Jing, warriors with good family background and high status (such as people with a family tree of 500-600 years) grow beards, while square beards are left by people with lower family background (such as veterans who gathered in the toilet of God in August 15).
Of course, it is also more hygienic.