Prepare and cut the chicken into slices. Place them in a bowl and set it aside.

Place the tomato ketchup, hoisin sauce, oyster sauce, soy sauce, and water in a small bowl. Stir everything using a teaspoon or a fork until you get a nicely emulsified sauce mixture. This is your katsu sauce.

Leave aside 2 tablespoons of the sauce, and add the remaining sauce to the chicken. Stir well until all chicken pieces are well coated with sauce. Here, you can pierce the poultry using a skewer or a fork. This will help the flavor to develop inside the chicken meat. Set it aside.

Wash, rinse, and cook the rice according to the instructions of the rice brand you get.

Once the rice is cooked, place it in a mixing bowl.

Mix the sugar, salt, and rice wine vinegar in a small bowl. Then add it to the rice as you mix the rice. Ensure the vinegar mixture is mixed thoroughly with the rice. Set it aside.

Heat the oil in the deep frying pan.

Dip the chicken pieces in the beaten egg, then roll the chicken onto panko breadcrumbs. Ensure all the pieces are well covered with breadcrumbs.

Carefully slide the panko-coated chicken piece into hot oil and fry at medium heat. Turn once until the chicken katsu is fully cooked and golden brown.

Rest the fried chicken katsu on a plate lined with a kitchen towel.

Take a serving bowl and spoon the seasoned rice into the bowl.

Add the lettuce, cucumber, and fried chicken.

Drizzle everything with the remaining katsu sauce.