Drain the bones. Wash the bones under running water. Add water, the onion, garlic, ginger and scallion. Bring it to a boil. Continue to boil over medium high heat. Reduce the heat to medium low. Continue to boil.
Bring a medium pot of water to a rapid boil. Blanch the cabbage until the white parts turn soft. Remove the cabbage from the pot and shock in cold water to stop the cooking. Drain and squeeze out water. Cut into 2 to 3-inch lengths.
Remove the meat from the broth. Discard the aromatic vegetables, reserving the broth (about 5 cups). Place the bone back in the pot with the broth. Add the cabbage, potatoes, and the remaining seasoning. Boil for about 10 minutes.
Throw in the perilla leaves and scallion. Add salt and pepper to taste. Boil for an additional couple of minutes, and then add the crushed perilla seeds.