Even though they may be located at the bottom of a valley, temples are metaphorically called mountains and even the numbers used to count them carry the ending , hence the name sangō. This tradition goes back to the times when temples were primarily monasteries purposely built in remote mountainous areas. The founding of a temple is called for this reason. No fixed rules for its formation exist, but the sangō is basically topographical in origin, as in Hieizan Enryaku-ji: these two names together mean "Mount Hiei's Enryaku-ji". For this reason it is sometimes used as a personal name, particularly in Zen. There may be however some other semantic relationship between the sangō and the san'in-jigō, as for example in the case of Rurikōzan Yakushi-ji. The sangō and the jigō are simply different names of the same god. Sometimes the sangō and the jigō are both posthumous names, for example of the founder's mother and father. Ingō The character , which gives the ingō its name, originally indicated an enclosure or section and therefore, by analogy, it later came to mean a cloister in a monastery. It is in this sense which it is applied to temples or, more often, subtemples. It can be also found in the name of formerly minor temples risen by chance to great prominence. For example, Kawagoe's Kita-in used to be one of three subtemples of a temple which no longer exist. Less frequent in an ingō are and . is normally used in the name of particular buildings of a temple's compound, e.g. Kannon-dō, but can be employed as a name of minor or small temples. Jigō The only name in common use is however the jigō, (ending in ) which can then be considered the main one. The sangō and ingō are not, and never were, in common use. The character -ji it contains is sometimes pronounced tera or dera as in Kiyomizu-dera, normally when the rest of the name is an indigenous name (kun'yomi). Unofficial names Temples are sometimes known by an unofficial but popular name. This is usually topographical in origin, as for example in the case of Asakusa's Sensō-ji, also known as Asakusa-dera. A temple can also be named after a special or famous characteristic, as for example in the case Kyoto's Saihō-ji, commonly called Koke-dera, or "moss temple" because of its famous moss garden. Unofficial names can have various