Vinegared Miso Sauce (酢味噌, Sumiso)

White miso looks quiet until vinegar wakes it. Sumiso is the small, glossy sauce we use for nuta, the dressed dish where scallions, wakame, squid, or shellfish get a thin coat and still remain themselves. It is not a sauce for hiding tired ingredients. Too much, and you've made a little bowl of miso with things trapped inside it, which is a less noble invention than it sounds.

Spring suits it best: young negi (Japanese long onion), nanohana (rapeseed greens), udo, fresh wakame, and boiled hotaru ika (firefly squid) all have the clean bitterness or sea-sweetness that sumiso knows how to hold. Sourcing comes first here. Choose vegetables at their 旬 (shun), when they're at their prime, and seafood that smells clean and sweet after boiling. The sauce should make them brighter, not louder.

The first secret is the order. Warm the miso, sugar, and mirin just enough to turn smooth and glossy, then add the vinegar off the heat. Boiled vinegar loses its clean edge, and scorched miso turns blunt. Warm to smooth, cool to brighten, rest to settle. Honmono is often no more mysterious than that.