In 1732, there was a great famine in western Japan caused by locusts. The famine claimed the lives of more than 17,000 people.
The price of rice rose 5 to 7 times. This enraged urban dwellers in Edo (Tokyo) who became rebellious. The government had introduced a new rice exchange just two years before the famine. People were suspicious of the government's role in the price increases. Mobs attacked the estate of a rice dealer and burned it to the ground.
In 1733, the Shogun (Yoshimune) approved a fireworks festival on Tokyo's Sumida river to improve the spirits of the masses. The Sumida Fireworks Festival was born.
Right from the start, the Sumidagawa fireworks was a rivalry between fireworks craftsmen. The two major houses of fireworks manufacturing (Tamaya & Kagiya) competed each year to win the crowd's affection. In the old days, the crowds would chant the name of their favorite team.
The competition went too far and in 1843 one of the teams burned down half the area with an errant round.
Today, the Sumidagawa fireworks is still a competition between fireworks craftsmen. It's great for the crowds — the fireworks are always cutting edge and designed especially for the show.
Many celebrants wear yukata to the event.
People show up early to put down a blue plastic mat with their name on it. This is the accepted way to reserve a spot for a party.
The Tokyo Metropolitan Police are always out in force to manage the large crowds.
The show is canceled in the event of rain. It's not possible to reschedule an event of this size. For one thing, the police are busy every weekend of the summer with Tokyo's many festivals.
When it's a go — the show is always spectacular.
Afterwards, thousands of amateur (intoxicated) people set off their own fireworks.
The Sumidagawa Fireworks is one of Tokyo's big 10 summer festivals. Check out the others here.