There is no saury in it. Despite what the name sounds like to a Japanese ear, sanma here is written with characters meaning fresh and to place on top. San for crisp and newly cut, ma for laid over. What that describes is bean sprouts and pork, stir-fried fast, thickened into a glossy sauce, and poured over soy sauce ramen.

The origin is contested. One shop says its head chef devised it in 1930 as a staff meal. Another, in business since 1918, credits its previous owner. Both accounts circulate in Yokohama and neither has driven out the other, which suggests the dish emerged from a kitchen culture rather than a person.

What is not contested is the sprouts. Every version has them, in quantity, and the whole architecture of the bowl exists to serve them. The starch in the sauce traps heat, so the sprouts arrive still snapping, which is what they would not do sitting loose in broth.

That strikes me as the actual invention. Not a recipe but a mechanism for keeping something cheap at its best moment for the length of time it takes to eat a bowl of noodles. The name wanders and the origin wanders with it. The sprouts, in every version anyone serves, hold perfectly still.