This is Anago Meshi made by the restaurant called Ueno.
Anago Meshi is Conger eels over rice.
The rice is not white rice, but is steamed with soup made from the bony parts of the conger eels and soy sauce.
It was started in 1901 as a station lunch box at Miyajima station.
The restaurant is located between JR Miyajimaguchi station and the ferry terminal to Miyajima in Hiroshima.
It seems that place is often crowded.
You can also buy it as a lunch box which is good even eaten cold.
By the way, Miyajima is a beautiful place especially in autumn.