Probably the oldest shrine in Edogawa-ku. Its home page tells us that it was founded on May 15, 938, and that its first Gūji was a shinjin (translates as both a godlike person or a low ranking Shintō priest) by the name of Yayama Sanahi (弥山左那比) who moved from Shinano Province in 932. At that time there seem to have been two shrines, Sengen Jinja and Shinmei-sha (神明社). In 940, when Taira Sadamori was sent by the central government to quell the Tengyo no Ran rebellion led by his father's killer, Taira Masakado, he prayed for success at a shrine called Itsukushima Jinja and donated, among other things, his bow and arrow to the shrine. Sengen Jinja emerged as the main shrine, with Shinmei-sha and Itsukushima Jinja becoming its in-ground shrines, the former under the name Tenso Jinja. Note that the kami of Itsukushima Jinja is Ninigi-mikoto, husband of the Sengen Jinja kami, Konosakuya-hime.
Thereafter the shrine prospered. Among its prized possessions are a sword which belonged to the 62nd emperor, Murakami, and a renga by the 102nd emperor, Gohanzono.
(Note: numbers in parentheses after kami names
From Merged Shrines
Shimo-Sengen Jinja 下浅間神社
Shimo-Sengen Mitake-Gū 下浅間御嶽宮
Katori Jinja 香取神社
Hachiman Jinja 八幡神社
Shirahige Jinja 白髭神社
Tenso Jinja/Suga Jinja 天祖神社・須賀神社
Itsukushima Jinja 霧島神社
Inari Jinja 稲荷神社
Yanagishima Inari Jinja 柳島稲荷神社
Annual Festival: July 1
Moving into the Edo Period, Edokawa-ku's oldest Jinja was swept up in the Mt. Fuji cult, as befits a Sengen Jinja. Although there is no Fujizuka in the shrine grounds there is a monument dating to 1840 to the founder of the Mt. Fuji cult, Jikigyo Miroku (食行身禄), who lived from 1671 t0 1733.
About 1.3 km from Shinozaki Station. It is quite spacious, it occupies a roughly 13,000 m² site, and well wooded. So well wooded in fact that in 1982 it was designated a Natural Monument by Edogawa-ku. Enjoyable as the rural ambience is, it is outweighed for me by the attractions of the 13 distinctive in-ground shrines, each of which is accompanied by its own notice board. However, there is one in-ground shrine, Yasukuni-Gū, which is not included in the list of 13 above, which is taken from the shrine's home page.
(Click on images to expand them)