Cut the pork belly into large chunks, about 2.5cm wide pieces. Blanch the pork belly pieces in boiling water for about 2 minutes, then drain and rinse well.
Slice into fairly large pieces, skin included. Reserve a thumb-sized portion – peel, julienne and set this aside for garnish. Trim the spring onions and separate the lighter bottom parts from the dark green tops. Finely chop the green parts and set aside with the julienned ginger for garnishing later
In a large saucepan, heat up the oil. Over medium heat, fry the ginger pieces until golden and fragrant. Push aside and add the pork belly, frying until just lightly browned
While the pork is frying, combine the barley miso, light soy sauce, mirin and water in a separate bowl, stirring to make sure everything is well mixed
Pour the miso mixture into the pan and bring everything to a boil over medium-high heat. Once boiling, cover and turn the heat down to low. Simmer gently for 2 1/2 hours, until the pork is very tender
Dish out into a large serving bowl and finish with the chopped spring onions and julienned ginger. Eat with plain rice or noodles, making sure to scoop the sauce over generously