Butterfly the chicken. Butterfly the chicken by slicing the breast horizontally along the long side of the chicken from one side leaving the other intact.
Tenderize and season the chicken. Fold out the chicken, and lightly pound the chicken to tenderize until it is about 1/2 inch thick then season both sides with salt and pepper.
Prepare the breading. Prepare three shallow dishes, 1) with flour, 2) with the lightly beaten egg and 3) with panko bread crumbs.
Coat the chicken. Thoroughly coat both sides of the chicken with flour, then the beaten eggs, and lastly the panko bread crumbs. Shake off any excess between each step and make sure to press on the panko bread crumbs to thoroughly coat the chicken.
Fry. In a medium-sized deep pan, heat up about 1-2 inches of vegetable or any neutral oil over medium-high heat until it reaches 340°F or 170°C. Place one coated chicken katsu into the oil and cook for 3 minutes before flipping and cooking for another 3-4 minutes. Cook the chicken until golden brown.
Serve. Let the chicken cool slightly on a wire rack before slicing into strips. Serve with rice, shredded cabbage and katsu sauce. Enjoy!