Sumashi Zoni

Sumashi zoni is a clear, soy-flavored New Year soup with round mochi rice cakes, eaten across Shimane Prefecture, though the ingredients vary by region. The eastern version is simple, made with just rock seaweed and bonito flakes, while the west uses dried ayu fish stock and sometimes adds tofu or konnyaku. In the Izumo region, rock seaweed from the Uppurui district of Izumo City is often used, giving the soup, together with bonito flakes, a rich oceanic flavor.

The broth's base varies by region and household — some use flying fish stock, others dried sardine or goby stock — and soy sauce rather than salt provides the main seasoning. The round mochi is boiled, not grilled, to soften it, and because simmering it directly in the broth would make it too soft, it is typically boiled separately and dropped into the broth just before serving. White mochi is used only for the first three days of the New Year; from the fourth day, some households traditionally switch to a mugwort-flecked mochi called "tenko mochi."

The rock seaweed harvested in the Uppurui district of Izumo City is said to have once been offered as tribute to the imperial court during the Nara and Heian periods, and its reputation is recorded in the "Izumo no Kuni Fudoki," a regional record compiled in the Tenpyo era. Making mochi at home was once commonplace, and pounding it at year's end and New Year is said to have symbolized family togetherness. Now that mochi is no longer a rare commodity, the custom of switching to tenko mochi on the fourth day is said to be fading, though the practice of using round mochi itself continues.