Akasaka Hie Jinja (赤坂日枝神社) is a Shinto shrine located at the heart of Tokyo and is a 3-min walk from Tameike-sanno Station of the Tokyo Metro Ginza Line or Namboku Line. For details about this shrine, see the article on Akasaka Hie Shrine.
A well-known festival called the Sanno Matsuri (山王祭) is held here in mid-June.

Sanno Matsuri at Akasaka Hie Shrine

The Sanno Matsuri, which is held at Akasaka Hie Jinja in mid-June, is another name for the Reitaisai, or the Annual Grand Festival, of the shrine. This festival is one of the most renowned traditional festival in Tokyo, but fully conducted only in even-numbered years. In the Edo period, along with the Kanda Matsuri of Kanda Myojin held fully only in even-numbered years, the mikoshi procession of this festival was allowed to enter the Edo Castle (modern-day Imperial Palace) for the Shogun to see it, thus being held in turn.

Events held every year

Even though it's fully implemented only in even-numbered years, small devotive events are held every year at the Sanno Matsuri.

This solemn ritual is the central component of the Sanno Matsuri, offering prayers to the shrine divinities.

Jinko-sai

The highlight of the Sanno Matsuri is the Jinko-sai, which is performed only in even-numbered years.
In this event, the spirits of gods enshrined at Hie Shrines are placed on two horen and one mikoshi, both of which are a type of portable shrine, and parade through the territory they protects.

Horses taking break at the National Theatre of Japan.

Rengo-togyo

There are also parades of mikoshi and dashi floats owned by local communites, which are also implemented only in even-numbered years.
The territory of the Hie Shrine can be divided into two areas - Kamimachi on the west side and Shitamachi on the east side. Large processions of community-owned mikoshi are held at Kamimachi on Saturday evening and at Shitamachi on Sunday noon.
Below are photos of the parade of Kamimachi.