Sannou-Matsuri(山王祭) is usually celebrated every two years on June at “Hie-shrine(日枝神社)” in Chiyoda Tokyo and the formal name is “hie-Shrine-Festival(日枝神社大祭)”.

The Three Great Festivals of EDO are “Kanda Matsuri(神田祭)“, “Sanja Matsuri(三社祭)” and “Sannou Matsuri(山王祭)” and the three great festivals of Japan are “Sannou-Matsuri(山王祭) in Tokyo” “Gion Matsuri(祇園祭) in Kyoto” “Tenjin-sai(天神祭) in Osaka”. However it’s also said that the three great festivals of Japan are “Kanda Matsuri(神田祭) in Tokyo” “Gion Matsuri(祇園祭) in Kyoto” “Tenjin-sai(天神祭) in Osaka”. You can feel atmosphere of Edo era like time travel because it’s held many kinds of events like Japanese traditional entertainment there.

Source of a Quote Wikipedia Sannou Matsuri(山王祭)
Dirk Beyer