What is the time of the ancient legend of Guan Gong grinding knife

"Guan Gong Sharpened Knife Festival", also known as "Guan Gong Sharpened Knife Day", is a traditional Chinese folk festival, people around the world have set up an altar to worship Guan Gong, to commemorate his loyalty, courage and righteousness to promote the virtues of the Chinese people, and to pray for the country's prosperity and peace of mind, the wind and the rain. Dongan Village's "Guan Gong Knife Festival" is a long history and rich in characteristics, to burn pigs to worship the festival, was recently selected as the third batch of Zhanjiang City, "Intangible Cultural Heritage" project list. The 13th day of the 5th month of the lunar calendar is a more "murderous" day in the traditional Chinese concept. Legend has it that Guan Yu became an immortal after his death, and the 13th day of the 5th lunar month is the day he sharpened his sword every year, so this day is characterized by a murderous spirit. People born on this day also have a strong murderous spirit and are short-tempered, especially women.

No scientific basis.