Suijin (水神, water god) is the Shinto god of water in Japanese mythology. The term Suijin (literally: water people or water deity) refers to the heavenly and earthly manifestations of the benevolent Shinto divinity of water. It also refers to a wide variety of mythological and magical creatures found in lakes, ponds, springs, and wells, including serpents (snakes, dragons, eels, fish, turtles), and the flesh-eating kappa. Mizu no kamisama, Mizugami, or Suijin, is popularly revered and worshipped in temples and continues to influence Japanese culture. Suijin is also known as the water god, Suiten (水天, "water heaven") and Sui-ō/Suiu (水王, "water lord").
Suijin is often conflated with Ryūjin, the Japanese dragon god associated with water. Fudō Myōō is sometimes called "Suijin" because of his believed association with waterfalls. Suijin appears as a stone plaque or even a small stone set upright near the emergence of a spring.
The Shinto water god is believed to be the guardian of fishermen and the patron saint of fertility, motherhood, and painless childbirth. People worship Suijin with offerings, believing that doing so will ensure pure and unpolluted water for drinking, agriculture, and sanitation, and will bring success in fishing trips, fertility, motherhood, and easy childbirth. Shrines devoted to the worship of the Water God are called Suitengū Shrines.
There are several numbers of shrines in Japan associated with deities. An example of this is the Horse God in Kurume, Fukuoka, the main shrine for all Suitengū Shrines in Japan. This shrine is visited by pregnant women who wish to ensure a safe and easy birth for their children. Another famous Suitengū Shrine is the Tsukiji Suijin Shrine, located near the Tsukiji fish market in Tokyo, which was built to protect and watch over the fishermen and their businesses.
Suijin is widely worshiped at Suitengū Shrines throughout Japan through votive stone markers devoted to the Water God. Most of these stone markers can be found enshrined at dikes, agricultural irrigation canals, rice paddy fields, mountain springs, regular springs, streams, rivers, wells, household wells, and even inside sewage water and septic tanks. When a Suijin stone marker is enshrined at mountain springs that form sources for agricultural waterways, it is often labelled as "water distributing god" (kumari no kami 水分神), in which case it may also be associated with the god of the mountain (Yama no kami 山の神).
There are many Japanese festivals dedicated to the water god, most of which occur during summer and winter, though more emphasis is placed on summer festivals. The majority of summer festivals occur at the Yasaka Shrine in Kyoto and the Tsushima Shrine in Tsushima. These observances have a significant role in the exorcism of bad spirits and purification, primarily aimed at dangerous epidemics, diseases and natural and man-made water-related disasters which commonly happen during the summer.
List of festivals worshipping Suijin (this list may not include all festivals):