The Metal Monkey day 庚申日

According to some Daoist beliefs one should not sleep in the night of a Metal Monkey day (geng shen ri 庚申日) .

The Daoists explain that there are three evil demons (san shi  三尸, literary "three corpses") residing in the body, also known as "the three worms". Once in two months, in the night of a Metal Monkey day (according to the sexagenary cycle in the Chinese calendar), while one sleeps, the three demons leave the body and go to heaven to report to the gods the sins of the person they inhabit.  Then the Heavenly god shortens the person's life span if he/she has comminted bad deeds.

In order to outsmart the three demons in the body, one should not fall asleep during the Metal Monkey day. Simple, isn't it? The Daoist practitioners use this time for meditation. By doing this, they believe the three demons stay calmly in the body and miss the opportunity to report one's sins to Heaven. The ordinary folks don't meditate, but are also awaken in the Metal Monkey night: everybody in the community will get together and sing and dance.

Some Daoist books point out to "Observe the Metal Monkey" (shou geng shen 守庚申). This term is also called "Keeping the three demons" (shou san shi 守三尸) and also "Killing the three demons" (zhai san shi 斩三尸). By doing meditation in this special day, it is believed that the demons will gradually disappear.

 Why this belief is related exactly to the Metal Monkey day is not thoroughly explained in the ancient texts. The stem and branch of this day both are Metal elements. Perhaps double Metal element is seen as "cutting" and shortening of one's life span? In Chinese astrology there are several Symbolic stars, which are related to abundance of Metal element and they signify danger of death, disasters or killing.

According to the old believes, these three demons are related to the three dan tian 丹田 - the energy centers in the body. The upper demon can disturb one's thoughts and cause bad vision and hair loss. The middle demon can cause  bad deeds, anxiety and overindulgence into eating and material desires. The lower demon makes one lewd and greedy.

The belief of the Metal Monkey day can be traced back to Han Dynasty in China, about 2000 years ago. During the Tang and Song dynasties it becomes very popular.  It is still performed nowadays in some Daoist monasteries.  Some Daoist internet sites even provide the dates of the Metal Monkey days in the year.

 It's interesting to notice how the belief about the Metal Monkey day has been spread in Japan, where it has became a part of the local folk traditions and Buddhism. In Japanese language this belief is called "Koshin" (Metal Monkey), which of course derives from the Chinese "geng shen" 庚申.  Since 9th century, all over Japan have been erected numerous "Metal Monkey pillars" - Koshin-to (庚申塔) for protection from the three demons.

The famous concept of the three wise monkeys comes namely from this Metal Monkey day belief in Japan. The three monkeys are known as Mizaru . They cover their eyes, ears and mouth, embodying the principle to "see no evil, hear no evil, speak no evil".