This is a regional specialty from Ehime Prefecture. A luxurious and delicious rice dish using leftover sashimi. The staff at the shop where I ate this described it as "raw egg with sashimi over rice."
I ate this at a friend's restaurant the other day and wanted to recreate it at home.
You can use other sashimi such as mackerel, bonito, pacific saury (the original dish calls for mackerel). You can pour hot tea for ochazuke!
Enjoy Japanese food around the world.