For a lively punch, few condiments are as reliable as yuzu kosho.

The spunky Japanese paste is a fermented pickle comprising the rind of the aromatic yuzu fruit, salt, and either red or green chilies (kosho in Japanese). Bottled in small jars, the intense condiment is akin to edible plutonium because a small amount goes a very long way.

Locally, the ingredient has been appearing at a variety of new restaurants. At ICHI Sushi in the Outer Mission, chef Tim Archuleta accents the singular brininess of raw oysters with a dot of yuzu kosho, along with pearls of tobiko and a ponzu bath.

Across town at Michael Mina's Bourbon Steak, a trio of duck-fat fries arrives as an amuse-bouche. The center pairing is fries dusted with finely ground shichimi togarishi (Japanese seven-spice) alongside an aioli laced with yuzu kosho.

Jason Fox of Commonwealth in the Mission is also a fan. "I love yuzu kosho," he proclaims. Currently, he dabs it on ribbons of sea urchin roe served with chrysanthemum, pickled scallions and sweet-potato tempura.

Little gestures, enormous flavor.