Also written 鳥栖; 鶏栖. Lit. "bird perch." At one time, torii were called uefukazu-no-mikado or uefukazu-no-gomon 於上不葺御門 (a roofless gate). The use of the honorific mi, go 御 allows the conclusion that such a gate was associated with Shinto shrines. An open gate-like structure composed of two posts or pillars *hashira 柱, connected by a top lintel *kasagi 笠木. Occasionally the structure was strengthened by a secondary or collateral lintel *shimaki 島木, attached to the underside of the top lintel with a tie beam *nuki 貫, placed below the lintels at a distance about equal to the diameter of the pillar. This distance had much greater variation before the 17th century. Exceptions are *toriimon 鳥居門 such as found at Ōmiwa Jinja 大神神社, or at Wakamiya 若宮 of Kasuga Taisha 春日大社, both in Nara, which have portals hung between the pillars.
Torii are usually erected at all entrances to a Shinto shrine to separate the hallowed precinct from its secular surroundings. They also serve to distinguish Shinto shrines from Buddhist temples. With the rise of Buddhist-Shinto syncretism in the 12th century, Shinto shrines began to appear within the grounds of Buddhist temples. Even then torii were used to mark the entrances to such shrines.
The origin of torii is unclear. Some scholars believe that the form derives from the torana gates found at the four points of the compass in the fence surrounding the Great Stupa at the monastery of Sanchi near Bhopal in central India. Other scholars believe that they are related to the bairō 牌楼 in China or the kōsenmon 紅箭門 in Korea. Furthermore, the Chinese kahyō 華表 or 花表 sometimes has been translated into Japanese as torii, but it is quite different. The Shōkahitsuyōki 匠家必用記 (1775) states that the kahyō is not the same as the Japanese torii. It has generally been accepted that torii were already in use by the late 8th century because of information given in Ruiju jingi hongen 類聚神祇本源 (Gathering Material on the Origin of Shinto), compiled in 1320. However, there is reason to doubt its reliability because mention is made of a *haiden 拝殿 which did not exist until the 10th century, and it was not called a haiden until the late 12th or early 13th century. Instead, the Izumi no kuni ōtori jinja rukichō 和泉国大鳥神社流記帳 (The Inventory of the Properties of Ōtori Jinja in Izumi, dated 922), is considered an accurate record and torii are mentioned. Therefore, it is certain torii were common by the mid-Heian period.
There is a possibility that torii originated in Japan. They may have developed slowly beginning in very ancient times before shrine buildings were deemed necessary. First, four posts may have been placed in the four corners of a sacred area and rope tied from one to the other to designate the boundaries separating the sacred from the mundane. The next step would have been to place two taller posts at the center of the most auspicious direction to form an entrance for the priest. Rope would then have been stretched from post top to post top. An example of two pillars connected only by a rope shimenawa 注連縄 can be seen today in front of the Ōmiwa Jinja Haiden. The use of the rope remains a way of denoting a hallowed place. Eventually, the rope was replaced by a wooden lintel. Because the structure was weak with only one lintel, a tie beam was added somewhat below the lintel and the simplest *shinmei torii 神明鳥居 came into being. The corner posts around the sacred area became true fence posts to support a simple wooden fence itagaki 板垣. Thus, the entire precinct was permanently enclosed. See *kaki 垣. Wood is still commonly used for small torii, and the oldest extant example from 1535 is the *ryōbu torii 両部鳥居 at Kubohachiman Jinja 窪八幡神社 in Yamanashi Prefecture.
The oldest example in stone, widely used until recently for its durability, is found at Hachiman Jinja 八幡神社 in Yamagata Prefecture and dates from around the middle of the 12th century. Occasionally, torii are made with copper sheeting placed over a wooden core. The oldest extant, dated 1455-57, is a *myōjin torii 明神鳥居 at the temple Kinpusenji 金峯山寺 in Nara. Many torii which may have originally been made of wood have been replaced by stone or reinforced concrete.
Although there are an infinite variety of torii named for unique characteristic, or for the name of the shrine itself, basically all torii can be classified under two major categories: those with straight members, shinmei torii, and those with curved members, myōjin torii. In both cases the terms are loosely applied to torii which fit these simple descriptions. However, shinmei and myōjin also refer to specific styles of torii. 1) Torii with straight members: shinmei torii ; *ise torii 伊勢鳥居, *kasuga torii 春日鳥居, *hachiman torii 八幡鳥居,*kashima torii 鹿島鳥居, *kuroki torii 黒木鳥居. 2) Torii with curved members: myōjin torii; *inari torii 稲荷鳥居, *sannō torii 山王鳥居, *miwa torii 三輪鳥居, ryōbu torii, *mihashira torii 三柱鳥居. Three famous myōjin type torii with some noticeably unique characteristics are referred to by the name of their shrines; shitennōji ishidorii 四天王寺石鳥居, *usa torii 宇佐鳥居, and *hakozaki torii 筥崎鳥居.
Before the premodern period, the proportion of parts of torii varied greatly. From the end of the 16th century, general dimensions were prescribed: the diameter of pillars should be about equal to 1/10 the distance from pillar center to pillar center. According to the *Shōmei 匠明 (Five Secret Books for Master Carpenters, 1608), the height of the pillar from the ground to the underside of the tie beam must be determined by a square constructed from the edges of the pillars. A circle is then inscribed. The underside of the tie beam coincides with the upper most perimeter of the circle. The projection of the tie beam is calculated by dividing its length into thirds from pillar center to pillar center. The ends of the tie beams should project 1/3 of that length. The slanted cuts *tasukizumi 襷墨 on the ends of the lintels are determined by a projected line nagarezumi 投墨 from the bottom center of the pillar to the upper or lower corners *uwakado 上角 or *shitakado 下角 of the tie beam.