Mitama Matsuri (みたままつり) is one of the popular summer festival in Tokyo. It happens at Yasukuni Shrine in the middle of July, which is Obon in Tokyo. There are over 30,000 Chochin, Japanese Lanterns, decorated every year. There are many events and food stands in this festival. Especially, Bon Odori is the earliest one in Tokyo.
Visitor's info.
Inside of the area of Shrine, you are not allow to eat and drink alcohol.
The lanterns will light after 18:00 to 21:30.
Access
0. at Tokyo Station.
1. walk to Otemach Station.
2. use Tozai Line to Kudanshita (4 min.)
3. walk west 810 min.)
2 hr.
New Wave Samurai Movie. 
映画好き集まれ！ 
Mitama Matsuri was started in 1947. About 300,000 people join this Matsuri every year. The purpose of this Matsuri is praying the rest in peace for all soldiers who had sacrificed their life to Japan and Japanese people. Those lanterns are showing the respects to them and praying the world peace.