Pacific saury is chopped with a knife. Miso, ginger, finely minced spring onion, and potato starch go in, and the mixture is rolled into balls. Then it goes into an oven or a pan and cooks until it browns. What you get looks like a hamburger made of fish, which is how people here describe it.

The name comes from the fire. Grilled over charcoal, the fat runs out of the saury, drops onto the coals, and the flames go up with a sound people write as popo.

There is a second explanation for the word, which is that you eat the thing while it is far too hot and end up blowing on it, popo, all the way through.

Its origin is a boat, and everything about it follows from that. Fishermen made this on board, in autumn, when the saury were fresh out of the water and there was no reason to carry them anywhere first. Iwaki has seven beaches, known collectively as the Iwaki nanahama, with fishing harbors ranged all along them, so this is not one village's dish but a coastline's. It is now taught at cooking classes in the city and served in primary school lunches. Both explanations of the name are about noise rather than about taste, which is unusual. The name of this dish is a sound that somebody heard on a deck.