Vinegar has been used in Japanese cooking since the Nara period, initially as a preservative and later as a flavour agent. Sunomono developed as a palate-cleansing course in formal meals — its acidity and lightness resetting the palate between richer preparations. The cucumber sunomono (kyuri no sunomono) is the most ubiquitous expression, present at every formal meal and most informal ones.
Sunomono — vinegared things — are lightly dressed salads of seafood, vegetables, and sometimes noodles dressed with sanbaizu (the fundamental Japanese vinegar dressing) or ponzu. The principle is economy of flavour: a small amount of rice vinegar, balanced with the dashi's umami and mirin's sweetness, produces a dressing that enhances without obscuring. Nothing in sunomono is heavy-handed.
**Sanbaizu (three-flavour vinegar):** - Rice vinegar, mirin, and light soy sauce in a ratio of approximately 3:2:1. The balance can shift depending on the ingredient. [VERIFY] Tsuji's specific sanbaizu ratio. - Bring mirin briefly to the boil to burn off alcohol before combining. This produces a rounder sweetness. - The dressing is made in advance and chilled — it is never applied warm. **Cucumber sunomono technique:** - Slice cucumber extremely thin (mandoline preferred — 1–2mm). - Salt generously, rest 5–10 minutes, squeeze out the water thoroughly. This firming and concentrating step is the technique; undressed cucumber releases water into the dressing and dilutes it within minutes. - Rinse briefly if too salty. Squeeze again. - Dress immediately before service. Never in advance. **Seafood sunomono:** Tako (octopus), ebi (prawn), and kani (crab) are the most common proteins. They must be cooked correctly for their specific texture — overcooked octopus defeats the purpose of sunomono's delicacy. Decisive moment: The salting and squeezing of cucumber — and specifically, the thoroughness of the squeeze. A hand-squeezed cucumber that still releases water when pressed against a cloth is not ready. The squeeze must be decisive and sustained — both hands, progressive pressure, until no more liquid runs. The firmness of the finished cucumber is the sensory confirmation: it should feel dense in the hand, not loose.
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