After visiting the Abashiri Prison Museum, I had lunch at Kangoku Shokudo. They recreate two prison set meals: A (saury) and B (mackerel) with barley rice and miso. They have other items on the menu. There’s a ticket machine to order food

However, the prison, when it was in operation, didn’t serve miso but bancha tea. I believe it due to Yoshie Shiratori who used miso to escape (worth a read on how he did it). Anway, I enjoyed this nice simple meal