In a large pot with enough boiling water, add ribs, cooking wine, ginger and scallion. Cook for 2-3 minutes until the ribs change color and turns pale. Transfer out immediately and drain.
Get a clean pot, transfer the ribs in. Add enough water to cover 2/3 of the ribs . Place sugar and light soy sauce in and 2 tablespoons of vinegar. Cover the lid, bring the content to a boiling and slow down the fire and simmer for 8 to 10 minutes. Remove the lid, use high fire to thicken the sauce until the sugar forms large bubbles in the pot. Add another tablespoon of vinegar, mix well and transfer out immediately.