The Sleepless Night: Unlocking the Mystery of Koshin Belief
If you have ever wandered through the quieter backstreets of Kyoto or hiked along the ancient Nakasendo trail, you may have noticed weathered stone pillars etched with the images of monkeys. These are not mere decorations; they are the silent sentinels of the Koshin Belief (Koshin-shinko), a fascinating syncretic folk faith that combines elements of Taoism, Buddhism, and Shinto. While largely faded from modern daily life, its remnants—specifically the famous “Three Wise Monkeys”—remain global icons.
The Origins of Koshin
The roots of Koshin belief lie in Chinese Taoism, specifically regarding the sexagenary cycle (the 60-year and 60-day calendar cycle). It arrived in Japan during the Heian period, initially practiced by the aristocracy before spreading to the samurai class and eventually the common people during the Edo period.
The word “Koshin” refers to the 57th combination of the sexagenary cycle: Kanoe-Saru (Metal Monkey). This specific day occurs once every 60 days, or six times a year. In the past, these nights were not for sleeping; they were for survival.
The Legend of the Three Corpses
At the heart of Koshin belief is a peculiar and somewhat terrifying legend regarding the human body. According to the tradition, every human plays host to three supernatural entities known as the Sanshi (Three Corpses) or Sanshichu (Three Corpse Worms).
These invisible worms reside in the head, the abdomen, and the feet. They are generally malevolent, keeping track of their host’s sins, bad deeds, and moral failings throughout the year. However, they are trapped inside the body as long as the host is awake.
On the night of Koshin, while the human host falls into a deep sleep, the Sanshi escape from the body and ascend to the heavens. There, they report the host’s sins to the Tentei (the Heavenly Emperor). Based on these reports, the Emperor shortens the lifespan of the human. A heavy sinner might lose hundreds of days from their life in a single night.
The Koshin-Machi Ritual
To prevent this celestial tattling, people developed a logical countermeasure: don’t sleep.
Villagers would gather for Koshin-Machi (Koshin Waiting). They would stay awake the entire night, drinking sake, chanting sutras, and engaging in communal festivities. By remaining awake, they kept the Sanshi trapped inside their bodies, preventing the worms from making their report and thus preserving their lifespans.
Modern Culture and the Three Wise Monkeys
While the all-night vigils have mostly vanished, the visual culture of Koshin remains potent. The most enduring symbol is the Three Wise Monkeys: Mizaru (See no evil), Kikazaru (Hear no evil), and Iwazaru (Speak no evil).
Because the word for monkey (saru) sounds like the negative verb ending (-zaru) in Japanese, the monkeys became associated with the Koshin day (Metal Monkey). Over time, they became guardians against the Sanshi. Their poses suggest a protective charm: “If we see, hear, or speak no evil, the Three Corpses will have nothing to report.”
The primary deity worshipped during Koshin nights is Shomen-Kongo (the Blue-Faced Vajra), a fearsome Buddhist protector often depicted crushing demons. He is believed to have the power to suppress the Three Corpse worms and prevent illnesses.
Traveler’s Tips: Where to Find Koshin History
For travelers interested in Japanese folklore, Koshin belief offers a hidden treasure hunt.
1. Look for Koshin-to (Koshin Towers)
Keep an eye out for stone slabs at crossroads in rural areas or older city districts. You can identify them by the engraving of Shomen-Kongo (often with six arms) or the Three Monkeys carved at the base.
2. Visit Yasaka Koshin-do (Kyoto)
This is the most photogenic Koshin spot in Japan. Located in the Higashiyama district, it is famous for its kukurizaru—colorful cloth balls representing monkeys with bound hands and feet. Visitors write wishes on them and hang them up. The bound monkey represents controlling one’s desires to achieve a wish.
3. Sanno Shrines
Because of the monkey connection, Koshin belief is often syncretized with the Shinto deity Sarutahiko Okami, the guide of the gods. Shrines dedicated to Sarutahiko often feature Koshin iconography.
Sources & Further Reading
- Nihon Shoki (The Chronicles of Japan): While Koshin is Taoist, the deity Sarutahiko Okami, often conflated with Koshin worship, appears here as an earthly deity who greets the grandson of the Sun Goddess.
- Taoist Scriptures: The concept of the Sanshi originates from the Baopuzi, an ancient Chinese text detailing methods of immortality.
- Japanese Folklore Studies: Works by Kunio Yanagita often reference the communal aspects of Koshin-Machi in Edo-era village life.