Simply Stir Fried Yokatta-Na

Preparation
Trim 1/4 inch from bottom of each head of bok choy. Slice bok choy crosswise into 1/2-inch-thick slices. Wash bok choy in several changes of cold water and dry in colander or salad spinner until dry to touch.
In wok or large sauté pan over moderately high heat, heat oil until hot but not smoking. Add ginger, scallions, and garlic and stir-fry until aromatic, about 15 seconds. Add bok choy, salt, sugar, and pepper and stir-fry 1 minute. Add 1 tablespoon water, cover, and cook until wilted, about 30 seconds. Uncover, stir-fry 5 seconds, then cover again, turn off flame, and let steam in residual heat until just tender, about 30 seconds more. Serve immediately.