In a small bowl, whisk together the Worcestershire Sauce, tonkatsu sauce, and soy sauce. Set aside.
Heat the oil in a large nonstick frying pan over high heat until shimmering.
Add in the onion and carrots fry for 1-2 minutes until slightly soft.
Add in the cabbage and fry for another 3-4 minutes until cabbage is bright green and slightly charred.
Add in the cooked noodles and toss to combine everything. Keep stirring the mixture so the noodles do not stick too much to the pan (some sticking is normal).
Keeping the heat high, pour in the sauce mixture and toss quickly to combine.
Let the noodles sizzle and crisp up in the pan until desired (2-3 minutes fo saucy yakisoba, 4-6 minutes for crispy and dried yakisoba).
Divide among serving plates and top with the pickled ginger, aonori flakes, bonito and Japanese mayo. Serve immediately.