Let’s prepare the meat. Cut the pork belly into 2~3cm (0.8″~1.2″) cubes.
Put the pork cubes in the heated non-stick pot. Fry them thoroughly on medium heat. No need to add oil, the fat will come out of the pork belly.
Fry the sides of the pork cubes.
Flip them over.
Fry each side of the pork until golden brown. This process will remove most of the fat from the pork. This will also prevent the pork cubes from breaking apart and help them look visually appealing when cooked.
When all the excess fat is removed, put the pork in another heavy pot. Remove the previous pot and heat the new pot on the burner.
In the meanwhile, cut the fresh ginger in half. Wrap the ginger root with a plastic wrap. Crush it with the side of the knife. The plastic wrap will keep the ginger pieces from scattering.
Put half of the ginger and the green part of the long onion in the pot. Pour a generous amount of lukewarm water into the pot. Heat the pot on high heat.
When it’s boiled, remove the foam with a ladle.
Reduce the heat to low and put a drop-lid on the pork. Simmer the ingredients for 2 to 3 hours.
When the water is reduced, pour additional lukewarm water. Make sure the pork is always submerged in the boiling water. A drop-lid is also called Otoshi Buta and it helps the meat cook evenly.
Remove the drop-lid. Pierce the pork with a bamboo stick and check if the inside is tender. Turn off the burner.
Put the pork cubes in a bowl of lukewarm water. Gently rinse the pork and place on the mesh strainer covered with a paper towel.
Wrap the pork with a paper towel and remove the excess fat and moisture thoroughly. Cool down the remaining cooking water in the pot and remove the solid fat. You can keep this and use as a stock for other recipes.
Let’s simmer the pork with the condiments. Arrange the pork cubes on the bottom of the heavy pot. Use a relatively small pot to let the pork submerge in the broth.
Add the sake, half of the ginger, kombu seaweed and lukewarm water to the pork. Heat the pot on medium heat. When it begins to boil, reduce the heat to low.
Put the drop-lid in the pot and simmer for about 20 minutes.
Remove the drop-lid. Add about 1/3 of the sugar and soy sauce to the pork. Even out the broth with the ladle. Replace the drop-lid and continue to simmer. Add the sugar and soy sauce in 2 or 3 steps, otherwise the meat tends to get tough.
When the broth is reduced like shown, add the rest of the sugar and soy sauce. Even out the broth with the ladle.
Reduce the broth while ladling it over the pork. Gently turn over the pork cubes. Handle with care as they can easily break into pieces.
Finally, add the mirin to make the surface of the pork glossy and visually appealing. Ladle the remaining broth over the pork. Reduce the broth a little and let the alcohol evaporate. Turn off the burner.
Slide the pork cubes to the side and make a space. Dip the soft boiled eggs in the broth. Let the pork and eggs soak up the broth while cooling down.
Heat the pork and eggs just before you serve. Cut the boiled green bean pods in half. Remove the eggs and cut them in half.
When the meat is warmed up, serve it in a bowl. Garnish with the egg. Dip the green bean pods in the broth and serve them in the bowl. Add karashi hot mustard to taste. Finally, pour on the hot broth.
A tip to making delicious tender Kakuni is to select a good pork belly that has clean layers of fat and lean meat.
Round parchment paper with a half inch hole in the center can be substituted for the drop-lid (otoshi buta).
Be careful not to reduce the broth too much since you will be cooking for a long time.
Using a pressure cooker, slow cooker or thermal cooker will help cook the pork belly easily.