Yūan-ji (柚庵地, Edo citrus-soy marinade)

Yuzu arrives when the air has gone sharp, and it carries winter in its skin. That is the right door into Yūan-ji: not a sauce poured over food, but a clear, fragrant bath that teaches fish or chicken to taste more like itself.

People make marinades too muscular. They add sweetness, acid, garlic, noise. We don't need it here. Equal parts shōyu, sake, and mirin give salt, fragrance, and gentle sweetness in balance, while thin slices of yuzu lend perfume from the peel. The juice is not the main worker. The skin is.

The one detail that decides it is time. Thirty minutes is enough for most fish fillets. Leave them too long and the soy tightens the flesh, the yuzu pith turns bitter, and the dish starts speaking too loudly. Nothing hidden. Brush it as it grills, let the surface gloss, and stop before the marinade becomes a mask.