Japanese Kakuni Pork Belly and Buta No Kakuni Braising

Kakuni (角煮, literally 'square simmered') is Japan's most celebrated long-braised pork belly preparation — a dish of striking tenderness, lacquered surface, and deep layered flavour that represents one of the pinnacles of Japanese nimono (simmered dish) technique. Originally derived from Chinese dongpo rou (東坡肉, red-braised pork belly), kakuni was adapted in Japan — particularly in Nagasaki through Chinese trade contact during the Edo period — into a preparation with characteristically Japanese restraint: sweeter, lighter in colour than Chinese versions, with sake and mirin providing background sweetness rather than the intense caramelised sugar of the original. The pork belly is cut into 5–8cm squares (the 'kakuni' name reflects this square cut), pre-blanched to remove impurities, then simmered in a dashi-enriched braising liquid of sake, mirin, soy sauce, and sugar for 2–3 hours until the collagen fully converts to gelatin and the fat renders to a trembling, melting softness. The braising liquid reduces and the pork is glazed by periodically basting with the reduced sauce. Quality kakuni requires: pork belly with alternating even layers of fat and lean (gosan no hire or standard thick-cut belly); the fat must not be too thin or it renders away entirely during the long braise, leaving only lean; and the final glaze must be glossy, not sticky-viscous.