The bridge washing of Meibashi Nihonbashi from around 11:00 on the last Sunday of July every year (the current bridge is celebrating 104 years this year).
I participated in 7/26.
First of all, thank you for visiting the "Japan Road Mark" embedded in the center of the bridge.
Then a long hose was taken out from the red body of the two Nihonbashi Fire Stations, and watered (recycled water) on the bridge.
Nature-friendly soapy water to the entire bridge with a bucket. (There are about 40 members from the fire department.)
The number of participants is men and women of all ages, maybe about 1500, or under 36 degrees below the scorching sun, all in groups.
Wearing the "Neighborhood Association-style happi coat" in hand, using deck brushes, etc.
Goshigoshi, take a bath to the bridge!
After 12:00, a large "Nihonbashi" sign with a ladder attached to both sides of the expressway above the head from the fire truck.
It's the finale for cleaning. Thank you very much during the hot weather.
(This letter is a copy of the nameplate of the bridge pillar written by Yoshinobu Tokugawa and is lined up side by side, but the nameplate of the bridge pillar is something that Yorinaka Tsumaki, an architect and shogunate, asked for the calligraphy.) 
