While walking around various cities and towns in Tokyo and many other prefectures, you might stumble upon various shrines or jinja each with its own torii gates, coming in all sorts of sizes and styles. These shrines and torii gates are usually structures to house and represent Shinto, the long-standing belief-system based in Japan and the kami, (deities and spirits) dedicated to that specific shrine. Today, there are more than 80,000 Shinto shrines that are still standing all across Japan!
Shinto is an animistic and polytheistic religion with no set religious figure or scripture and mainly focuses on the belief in nature, one's own well-being and kami. Shinto and its beliefs originated from the olden times in Japanese society--there is no single or specific creator or original scriptures that pinpoint the origins of Shinto. While there is no set definition for Shinto, there are a variety of beliefs and aspects of life associated with Shinto. As already mentioned, kami are the various deities or spirits that are associated with Shinto, being present everywhere and anywhere all at once; they are also one of the main focuses of Shinto practices and traditions.