Shojin ryori is based on the principles of Buddhism, namely not hunting any living animal for the purpose of food. In other words, shojin ryori does not use fish, meat or other animal products such as eggs. In addition, strong tasting vegetables such as leeks, onions and garlic are avoided as it is believed that they will hinder the pursuit of discipline. Shojin ryori is the style of food that was originally eaten by disciples of Buddhism. The fact that this simple style of vegan food was eaten in temples during the Heian period (794 to 1185 AD) that followed the introduction of Buddhism in Japan is mentioned in the famous piece of classical literature "The Pillow Book" by Sei Shonagon. The food made at pilgrim lodgings, originally opened by Japan's well-known Buddhist monk, Kukai Kobo-Daishi, in the Koyasan region is particularly famous.
Towards the end of the Heian period (about 760 years ago) another well-known Japanese monk and founder of the Soto Zen School, Dogen, went to study Buddhism in China. He witnessed the daily workings of temples there and wrote two books detailing his experiences. His first book detailed preparation and cooking methods, while his second dealt with etiquette and table manners. It is because of these two books that this traditional style of cooking has been preserved today, especially with relation to the Soto Zen School of Buddhism.