2 lb. beef tenderloin or top round, sliced very thin

(I usually double the following)

3 tbsp. soy sauce (Kikkoman sauce is best)
2 tbsp. sugar
1 tsp. pepper
2 tbsp. sesame oil or other vegetable oil
1 large onion, sliced
Garlic powder (1/8 - 1/4 tsp.)

NOTE: I add about 1 tablespoon of sesame seed too. (If you want, you can add 2 tablespoons sake to this, but it is optional.)

Place sliced meat in large, shallow pan. Pour marinade over beef. Mix all and marinate for at least one hour (I let it sit all day--with final hour at room temperature).

Broil over charcoal - watch carefully as it will cook fast - serve immediately with bowls of hot rice.

You could marinate one chunk of meat too, but score the meat to allow marinade to penetrate.