Instead of chicken, you can also use think pork cutlets. You can also use delicious menchi katsu (minced meat). Using the same technique of pouring over the eggs, you can use all kinds of other meats or fish instead of fried cutlets. I'll often use thin slices of beef or pork marinated in soy and sesame oil. A quick flash fry and then they're topped over the onions as usual. I also like to use salmon cutlets fried until just cooked then top the onions and add the eggs. Delicious.
The perfect garnishes
I like to keep it simple with my garnishes and serve with some seaweed flakes, thinly sliced scallions and some pickled ginger.