Found all across Japan, the Torii Gates can usually be spotted at the entrance or inside a Shinto Shrine, and they mark the entrance from the profane to the sacred.
However, there are many types of Torii! In the picture below you can find some of them.
From the upper left corner:
1 – Shinmei Torii – One of the two big families of Torii. It is famous for its straight parts. Being believed to be the oldest Torii style, it is constituted solely by a lintel (kasagi) and two pillars (hashira) united by a tie beam (nuki). In its simplest form, all four elements are rounded and the pillars have no inclination.
2 – Yasukuni Torii – A subtype of the Shinmei Torii, characterized by a rectangular nuki in section. Can be found at Yasukuni Shrine in Tokyo.
3 – Myōjin Torii – The second of the two big families of Torii. On the contrary of Shinmei Torii, this family of Torii also has curved parts.
4 – Kasuga Torii – It is a Myōjin Torii with straight top lintels. The pillars have an inclination and are slightly tapered. The nuki protrudes and is held in place by kusabi driven in on both sides. This Torii was the first to be painted vermilion and to adopt a shimaki at Kasuga Taisha in Nara.
5 – Kuroki Torii – It is a Shinmei Torii built with unbarked wood. Because this type of Torii requires replacement at three years intervals, it is becoming rare. The most notorious example is Nonomiya Shrine in Kyoto. The shrine now however uses a torii made of synthetic material which simulates the look of wood.
6 – Kashima Torii – It is a Shinmei Torii without korobi, with kusabi and a protruding nuki.
7 – Nakayama Torii – It is basically a Myōjin Torii, but the nuki does not protrude from the pillars and the curve made by the two top lintels is more accentuated than usual.
8 – Hachiman Torii – It is almost identical to a Kasuga Torii, but with the two upper lintels at a slant, the Hachiman Torii first appeared during the Heian period.
9 – Munetada Torii – It is a Shinmei Torii (straight lines) with a slight change in form. The best example of it is the second Torii in the Munetada Shrine in the Yoshida Hill, Kyoto.
10 – Naiguugen Torii – Famous for its 8-sided pillars and the kasagi being a pentagonal prism, with both sides diagonally cut.
11 – Ryoubu Torii – Also called Yotsuashi Torii (lit. four legged torii), the Ryōbu Torii is a Daiwa Torii whose pillars are reinforced on both sides by square posts. The famous torii rising from the water at Itsukushima is a Ryōbu Torii, and the shrine used to be also a Shingon Buddhist temple, so much so that it still has a pagoda.
12 – Sannou Torii – It is Myōjin Torii with a gable over the two top lintels. The best example of this style is found at Hiyoshi Shrine near Lake Biwa.
These are just some of them! There are many many more!