Rendan beard refers to the figure-eight beard on the trademark image of Rendan in Japan. It is very popular in Japan, and it is not uncommon in the upper echelons of the Soviet Union. At least half a dozen generals have this kind of beard.
It originated from a great companion of four officials in heian period, Jin Mao, who was at odds with the then Taisho minister Fujiwara. All Fujiwara's "servants" wore mustaches, so the great companion ordered his own "servants" to keep square beards to show that they would never compromise with Fujiwara.
Later, Fujiwara family designed to encircle 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. If you can kill or capture Jin Mao alive, you can seal the reward. More than 7 "servants" under Jin Mao surrendered or defected, and all of them died under Jin Mao's leadership. This spirit was rewarded by everyone, including Fujiwara, and Ji An personally set up a monument to commemorate them.
Since then, the square beard has become the "symbol" of many warriors, expressing their loyalty and courage. This is the reason for their beards. Generally, in Japan, A warrior with a good family background or a descendant of a warrior with a high status (such as a person with a family tree of 5 to 6 years) has a mustache, while a square beard is left by a person with a lower family background (such as a veteran of Japan before World War II, who often has a square beard is a businessman from his ancestors or a civilian since his grandfather).