Cook the Noodles: Cook yakisoba noodles in boiling water with a pinch of salt until al dente. Drain and set aside.
Fry the Noodles: Heat oil in a wok or large frying pan. Fry the noodles until toasted, then set aside.
Brown the Pork Belly: In the same pan, brown the thinly sliced pork belly until caramelized. Remove excess fat.
Sauté Vegetables: In the center of the wok, sauté carrots, onions, bean sprouts, broccoli florets, and red and green cabbage.
Combine and Season: Return the noodles to the pan with the vegetables. Add the sauce ingredients (oyster sauce, soy sauce, Worcestershire sauce, sake mirin, sugar, black pepper, sesame oil, and rice vinegar) and mix well.
Final Touches: Finish with chopped fresh ginger and chives to taste.