The Sumidagawa Fireworks Festival (隅田川花火大会, Sumidagawa Hanabi Taikai) is an annual fireworks festival held on the last Saturday in July, over the Sumidagawa near Asakusa. Unlike fireworks displays in other parts of the world, the Sumidagawa Hanabi Taikai follows the Japanese tradition of being an intense competition between rival pyrotechnic groups. Each group tries to out-do the last, and the result is an incredible variety of fireworks, not just in different colors and patterns, but forming shapes as complicated as Doraemon, Pikachu, or kanji.
Originally called Ryōgoku Kawabiraki (両国川開き), the display had become an established tradition by 1810, and rivalries began to emerge over control of each year’s festival. The Tamaya (玉屋) and Kagiya (鍵屋) guilds of pyrotechnicians quickly became the two major rivals, initiating the tradition of the competition. Each guild would try to impress the onlookers, out-doing the other guild, in order to gain popularity and support. The number of onlookers steadily grew, and they began to shout out the names (see yagō) of their favorite fireworks artists.