Step 1

Place 1 chicken thigh skin side down on cutting board. Using sharp paring knife, trim excess skin and fat, leaving enough skin to cover meat. Cut slit along length of thigh bone to expose bone. Using tip of knife, cut/scrape meat from bone. Slip knife under bone to separate bone from meat. Discard bone and trim any remaining cartilage from thigh. Keeping thigh skin side down, cut into 1½-inch pieces, leaving as much skin attached as possible. Transfer to medium bowl and repeat with remaining thighs. Add 1½ tablespoons sake and cornstarch and stir gently until chicken is evenly coated.

Step 2

Combine soy sauce, sugar, and remaining 2 tablespoons sake in small bowl. Microwave until sugar is dissolved, about 30 seconds. Place fine-mesh strainer over bowl containing soy sauce mixture. Add ginger to strainer and press to extract juice. Discard solids, but do not wash strainer.

Step 3

Line large plate with paper towels. Heat oil in 12-inch nonstick skillet over medium heat until shimmering. Place chicken skin side down in skillet (skillet may be very full). Increase heat to medium-high; place Frywall or splatter screen, if using, on skillet; and cook, without moving chicken, until all pieces have ¼- to ½-inch perimeter of white, 6 to 8 minutes. Slide skillet off heat and flip chicken. Return skillet to burner and reduce heat to medium. Continue to cook until chicken is just cooked through, 1 to 2 minutes longer.

Step 4

Remove skillet from heat. Using slotted spoon, transfer chicken to prepared plate. Pour off fat, scrape any browned bits out of skillet, and wipe skillet clean with paper towels. Return chicken to skillet. Add soy sauce mixture and cook over medium heat, stirring frequently, until chicken is thinly coated and sauce has consistency of maple syrup, 1 to 2 minutes. Using slotted spoon, transfer chicken to serving bowl. Pour glaze in skillet through now-empty strainer set over small serving bowl. Drizzle 2 tablespoons glaze over chicken and serve, passing remaining glaze (there will be only a few tablespoons, but it is potent) separately.