The frog is a symbol associated with rain at the Yasaka Shrine

An event called the Tsukumai event, is held on the last day of the Gion Festival at the Yasaka Shrine in Ibaraki, to pray for rain and a good harvest for the year.

A man wearing a special costume and the mask of a frog climbs up a 17-meter pole to the rhythm of the drums. Once on top, he performs such stunts as tight-rope walking and standing on his head. He then shoots arrows to the north, south, east, and west. Any person who picks up an arrow will be blessed with good fortune for the year. This tradition has continued for over 500 years.

The Gion Festival of Yasaka Shrine

The Yasaka Shrine located in the uptown section of Ryugasaki city is the site of the famous Gion Festival. This shrine was built as a satellite of the Kaiharazuka Yasaka Shrine in the Bunji era (1185-1190). This festival is held July 25 to 27 every year, when the mikoshi (sacred shrine) is carried on the shoulders of worshipers, who stroll the streets.

Source: The Ryugasaki Hometown website http://hometown.infocreate.co.jp/en/kanto/ryugasaki/maturi-e.html