Monkeys are good at climbing trees and like playing jokes, so it is no wonder the Japanese are fond of them. The Japanese word for monkey is "saru," which may come from the fact that monkeys like to fool around (zareru).
Japan has only one wild species of monkey (nihon-zaru, or Japanese monkey, a cute variety in the Macaca genus). Perhaps that is why, over the centuries, people in Japan have had an unchanging idea of what monkeys are like.
In the West, the image conjured up by monkeys may be different people there might be more familiar with the baboon, whose face resembles that of a dog. Such a monkey tends to remain on the ground, like the dog-faced baboon god of ancient Egypt. The image Oriental people have of monkeys may be different from that in the West.
In the West, monkeys are sometimes identified with devils, or the corrupt side of human beings. In some places in the Orient, on the other hand, they were revered as godlike creatures. In countries where Hinduism is practiced, they are identified with the brave Hanuman, a hero who had unusual powers. Hanuman was strong enough to carry a Himalayan mountain, and his story is said to have inspired the famous Chinese story of the legendary monkey hero, Sunwukong. The monkey probably appears in the legend because he is intelligent and skillful with his hands and tail.
In China, people used to say that keeping a monkey in a stable would prevent horses from getting sick. This custom spread to Japan. This is another example of how monkeys were thought to have special powers.
The Chinese calendar consists of two elements the juni-shi (the 12 animal signs of the zodiac), and the jikkan (the 10 stems representing things, grouped under the five elements). Duplications are removed from combinations of these to give a cycle of 60 units of time. Thus, each designated day occurs once every 60 days. The most magical of these days is called koshin no hi, one of the days of the monkey. Years ago, on the night of this day, it was a Chinese custom to celebrate until dawn. This is because it was thought that the sanshi, three bad worms living inside each person's body, would rise up into the sky during one's sleep to report the person's sins to the King of Heaven. The person's remaining days on earth would be reduced by a number of days depending on the severity of the sins. By staying up all night, people tried to prevent the sanshi from leaving the body. Koshin no hi was a critical time, because it was the day when one's life could be shortened!
When this belief spread to Japan, the festival became a time to stay up all night and pray to the monkey god for a long life. One monkey god, Sanno Gongen, is revered at Hie shrines in Japan.
People thought that if they practiced "See no evil, hear no evil, speak no evil," the sanshi could not shorten their lives because their sins, and those of others, would go unnoticed. From this belief sprang the Three Monkeys, now known throughout the world.
One dosojin guardian deity of roads, called Sarutahiko, took the shape of a monkey, so this god was revered together with Sanno Gongen on koshin no hi days. That was a time to celebrate into the night and ask for something special.
In one of Japan's most famous children's stories, Saru Kani Gassen (The Battle of the Monkey and the Crab), a bad monkey tricks a crab and takes all her persimmon fruit away from her. There was an old belief that persimmons have magical powers that bring the birth of children and a good harvest. Perhaps the monkey was the most suitable animal for this fable because he had the ability and intelligence needed to keep something magical for himself. In the fable, a bee, a walking chestnut, and other creatures all smaller and weaker than the cunning monkey defeat the monkey. It may be that children love this story because small creatures win in the end.
Incidentally, there is a Japanese saying, "Saru mo ki kara ochiru
." This means, "Even monkeys fall out of trees," or as the English expression has it, "Pride comes before a fall."