Fireworks festivals are one of Japan's key summer traditions, and you'll find them held in big cities, small towns, and everywhere in between. The Inagawa Fireworks Festival has been running for over 70(!) years now, and it sees around 4000 fireworks launched from the banks of the Ina River.
There are several different viewing areas for the event, on both sides of the river. More information about those can be found on the official website.
Please note that in the event of inclement weather, the festival will be canceled (not postponed). Any decision to do this will be made by 3pm on the day, so keep an eye on the official website for updates.