Prepare seasoned pork liver. Soak pork liver in milk for 10 minutes. Drain and pat dry with a paper towel. Season with koikuchi soy sauce and sake for 5 minutes.
Mix sauce ingredients together in a bowl. Set aside.
Heat oil in a pan over medium heat. Stir-fry pork liver for 1 minute. Add chilli bean paste and fry briefly. Remove from heat and set aside.<