Cut the pork belly into 4 equal pieces to fit the pot.

Trim the bok choy roots slightly and cut into quarters lengthwise. Blanch in boiling water, then rinse under cold water and squeeze out excess moisture.

Heat salad oil in a frying pan over medium heat and sear the pork belly until browned on all sides.

Place the seared pork, green onion (green part), and ginger slices in a pot. Add enough water to cover the pork and bring to a boil over high heat. Reduce to low heat and simmer for 1 hour.

Separate the pork from the broth. Cut the pork into bite-sized pieces.

Wash the pot, then add the pork, broth ingredients (boiling water, sake, sugar, ponzu sauce, ginger), and bring to a boil over medium heat. Reduce to low heat, cover with a drop lid, and simmer for 30 minutes.

Turn off the heat, add the soft-boiled eggs, and let sit for 20 minutes.