Cut the potatoes in half, then slice each half horizontally. Soak in water, drain, and microwave with 1 tbsp water for 5 minutes at 600W. Drain well.

Pierce the spare ribs with a fork in several places and season with salt and pepper.

Heat salad oil in a pan over medium heat. Add the spare ribs and cook until browned on all sides. Remove excess fat with a paper towel. Add sake and water, bring to a boil, cover, and steam for 10 minutes until cooked through. Remove the lid and cook over medium-high heat to evaporate excess liquid.