tokyo festival in september

I would be in tokyo from sep 17 to sep 26. I would like to attend a festival. I saw online regarding Nezu-jinja (sep 21) there is suppose to be a festival ceremony. What is it? Is it a prayer ceremony where the public can view or is it like a event festival. And what time does it actually start? Please let me know if there are any other festivals that I can attend. Thanks

There is a festival at Setagaya Hachimangu shrine. Unfortunately the sumo event (very funny) is on the 16th. The Matsuri continues on The 17th though.

https://setagayansson.com/news/setagayahachiman_20170916

The Matsuri at Nezu ninja seems to finish on the 16th: https://www.gotokyo.org/jp/kanko/bunkyo/event/nedujinja-reitaisai.html

A Matsuri in Ikebukuro seems to be on while you are in Tokyo:

https://www.gotokyo.org/eventlist/ja/list

Enjoy your Matsuri experience!

Here are some traditional ones.

17 Sep Hamamatsucho: Shiba Daijingu Daradara Matsuri 9:00-19:00
http://www.shibadaijingu.com/20180810/2018_reitaisai.pdf
https://www.enjoytokyo.jp/amuse/event/361877/

17 Sep Kameido: Koto Tenso Jinja Shinmei Matsuri 17:00:-20:00
https://www.enjoytokyo.jp/amuse/event/655551/
http://www.tensojinja.com/access/

22 Sep Ikebukuro: Fukuro Matsuri / Eve
23 Sep Ikebukuro: Fukuro Matsuri / Mikoshi
https://www.yosakoitokyo.gr.jp/
https://www.gotokyo.org/jp/kanko/toshima/event/fukuro1.html
https://livejapan.com/ja/article-a0002302/

Others are some many. Need to specify date and preference.
https://www.enjoytokyo.jp/feature/matsuri/autumn/sept/007.html
https://www.walkerplus.com/event_list/20180917/ar0313/