noun
river-opening festival; start of boating season
A traditional summer event held at rivers, often featuring fireworks and boat rides, marking the beginning of the boating and river recreation season.
隅田川の川開きでは、毎年花火大会が開かれる。
At the Sumida River opening festival, a fireworks display is held every year.
川開きの日には、たくさんの屋形船が川に浮
On the day of the river-opening festival, many pleasure boats float on the river.