One of the most loved comfort foods in Japan, the secret for meltingly tender pork is its slow simmering in rice. Kakuni means square in Japanese, so cut the meat as squarely as you can.
Heat the oil in a large, heavy casserole (Dutch oven) over a medium-high heat. Add the pork belly, skin side down, and sear for about 5 minutes until golden brown. Turn over and brown on the other side for about 5 minutes more. Transfer to a colander and rinse under hot water to remove any excess oil. Pour off and discard the fat from the casserole (Dutch oven), then wip