or is a folk belief in Japan with Taoist origins, influenced by Shinto, Buddhism and other local beliefs.
An event related to the belief is called , held on the KÃ Âshin days that occur every 60 days in accordance with the Chinese sexagenary cycle. On this day some believers stay awake to prevent , entities believed to live inside the bodies of believers, from leaving during that night in order to report the deeds of believers to the god Tentei.
It is not known when this belief arrived in Japan, but it was widespread among the nobles of the imperial court by some time in the 9th century. The Japanese monk Ennin, visiting Tang China in 838, wrote that "This night no one sleeps. It is the same as New Year's Eve and the nights of KÃ Âshin in our country." In the Muromachi period, Buddhist monks started to write about KÃ Âshin and spread the belief to a wider public. Numerous monuments or pillars called (or also ) were erected all over the country, and the belief remained very popular during the Edo period. However, after the Meiji government issued the Shinto and Buddhism Separation Order in 1872, KÃ Âshin and other folk beliefs were officially rejected as superstitions.
Belief in Kà Âshin survives, although it is far less popular than it once was. Many Kà Âshin-tà  have been moved inside Buddhist temples or private homes, but many remain alongside roads and there are still some well-maintained (Kà Âshin halls) either attached to Buddhist temples or standing alone.
The most ancient Kà Âshin custom is that of staying awake one special night every sixty days. This night is called Kà Âshin-Machi (åºÂç³徠- Kà Âshin Waiting).
The main Kà Âshin belief is the concept that Three Corpses, or Sanshi (ä¸Âå°¸), live in every human body. The Sanshi keep track of the deeds of the person they inhabit. On the night called Kà Âshin-Machi, the Sanshis leave the body and go to Tentei (天å¸Â), the Heavenly God, to report the deeds of that person. Tentei then punishes bad people, making them ill, shortening their lifespans or, in extreme cases, ending their lives. Believers in Kà Âshin try to live without performing bad deeds, but those who believe that they have reason to fear try to stay awake during Kà Âshin nights, as the only way to prevent the Sanshi from reporting to Tentei.
In the Edo period, Kà Âshin-Machi became more popular among commoners, leading to a proliferation of festivities and cultic activities. Many of these practices centered on the worship of specific deities. These deities were visualized in hanging scrolls, icons, and stone carvings, many of which continue to dot the rural landscape of Japan today. One specially prominent god in the Kà Âshin cult was Shà Âmen-Kongà  (Blue-Faced Vajra-Yaká¹£a), a fearsome deity with many arms. The first scriptures that established his connection with Kà Âshin were produced in the context of esoteric Buddhist rituals performed at the temple known as or . Another temple crucial in the early development of this cult was Shitennà Â-ji. Shà Âmen-Kongà  became Kà Âshin-san when people expected this deity to make the Sanshis themselves ill and prevent them from going to Tentei.