Cook the Japanese rice according to package instructions. In a small bowl, whisk together ketchup, Worcestershire sauce, soy sauce, and sugar until fully combined. Set aside.

Pat the chicken breasts dry. Set up a dredging station with three shallow dishes: one with flour seasoned with salt and pepper, one with the beaten egg, and one with the panko breadcrumbs.

Coat each chicken breast first in the flour, then dip in the egg, and finally press firmly into the panko breadcrumbs, ensuring an even, thick coating.

Heat about 1 inch of oil in a large skillet over medium-high heat to 350°F (175°C). Carefully lay the chicken in the skillet and fry for 3-5 minutes per side, until golden brown and cooked through. Transfer to a wire rack to drain.

Slice the cooked chicken katsu into strips. Divide the cooked rice between two bowls. Top with shredded cabbage and the sliced chicken. Drizzle generously with the homemade tonkatsu sauce before serving.