Japanese Kakuni Braised Pork Belly Shoyu and Sake Method

Ingredients

• 1 kg pork belly, skin-on, in one slab
• For the braising liquid
• 200 ml sake
• 100 ml mirin
• 100 ml soy sauce, Japanese-style shoyu
• 30 g sugar, white or brown
• To garnish
• 4 eggs, soft-boiled or simmered
• 200 g bok choy or spinach, blanched
• At table
• 1 tsp karashi, Japanese hot mustard, served separately

Method

1. 1
   Place the pork belly slab whole in a pot and cover generously with cold water. Bring to a simmer and cook, uncovered, for 60–90 minutes, skimming any foam that rises. The pork is ready for the next stage when a skewer meets only faint resistance through the thickest point and the surface fat has visibly contracted.
2. 2
   Lift the slab from the pre-cooking liquid and allow it to cool until handleable. Discard the pre-cooking liquid entirely — a clean start is essential to an unmuddied sauce. Trim the slab to neat geometry and cut into squares of approximately 4 × 4 cm. The cooled protein should feel firm and hold a clean edge under the knife.
3. 3
   Combine the sake, mirin, soy sauce, and sugar in a heavy pot or deep sauté pan wide enough to hold the squares in a single layer. Bring to a gentle simmer over medium heat, stirring until the sugar has fully dissolved. The liquid should smell of concentrated soy-sake sweetness with no sharp raw-alcohol edge.
4. 4
   Nestle the pork squares into the braising liquid, skin side up. Place an otoshibuta (drop lid) directly on the surface of the squares. This is where the dish lives or dies: reduce the heat to the lowest possible setting and maintain a barely perceptible simmer — the collagen converts to gelatin at 70–80 °C; heat above this range will tighten and toughen the lean muscle irreversibly. Braise for 60–90 minutes without disturbing the squares. The liquid will reduce and thicken; the skin will turn translucent.
5. 5
   Remove the otoshibuta. The sauce should coat the back of a spoon in a thick, glossy mahogany film — not watery soup. If the sauce is still thin, remove the pork squares briefly to a dish and reduce the liquid over medium heat until it reaches a spoon-coating consistency, then return the squares and turn them once to glaze.
6. 6
   Remove from heat and allow the pot to cool to room temperature, then refrigerate overnight in the sauce. The following day, gently reheat the squares in the sauce over low heat. The fat layer in a properly rested kakuni is gelatinous, barely solid, and nearly liquid at body temperature; the lean meat yields without resistance. Taste the sauce — it should carry deep mahogany sweetness with clear soy-sake depth.
7. 7
   Serve each portion with one simmered egg, a portion of blanched bok choy or spinach alongside for colour and freshness, and a spoonful of the reduced sauce spooned over. Pass karashi separately at the table.