Rakkyo (Allium chinense) is a small, crisp Chinese-Japanese onion eaten almost entirely pickled — plump, pearly teardrop bulbs, each no bigger than a fingertip, brined in sweet rice vinegar until they turn translucent, tart and audibly crunchy. A culinarily distinct allium species rather than a young onion, it is the classic ruby-and-white pickle set beside a plate of Japanese curry rice, its sharp, sweet, garlicky bite cutting the richness of the roux. In China the same species is known as jiaotou or xiao suan (little garlic) and is salted, soy-cured or fermented; in Japan it is amazu-zuke rakkyo, sweet-vinegared, sold in jars and eaten as a side pickle, a curry condiment, and a folk pick-me-up. Where most alliums melt and sweeten with cooking, rakkyo is prized for staying raw and crackling — a pickle first and a vegetable second.