Cut 300 g boneless chicken thigh into bite size pieces.
Take a container and add 1 tbsp Japanese soy sauce (koikuchi shoyu), 1 tbsp sake, ⅛ tsp ground black pepper, 1 tbsp grated garlic and 1 tsp grated ginger root. Mix to combine and add the chicken pieces. Mix until fully coated and marinate in the refrigerator for 30 minutes.
While waiting for the chicken to marinate, add 1 tsp grated ginger root, ½ tbsp grated garlic, 1 tbsp Japanese soy sauce (koikuchi shoyu), 1 tbsp mirin, 1 tbsp sake, 1 tbsp honey, 1 tbsp water, 1 tsp rice vinegar and 1 pinch ground black pepper to a small sauce pan. Bring to a boil over medium heat, then lower to medium-low and simmer for 1-2 minutes. Set aside for later.
After 30 minutes, add 3cm (just over 1 inch) of cooking oil to a deep pan and heat to 160 °C (320 °F). While you're waiting for it to heat up, sprinkle about 5 tbsp potato starch (katakuriko) onto a plate and take the marinated chicken from the fridge. Coat each piece evenly with starch, making sure to shake off the excess marinade before coating.
Once the oil is hot, add the chicken pieces and fry for about 3 minutes on each side.
Increase the heat to 190 °C (374 °F) and fry for 1 minute on each side.
Transfer to a wire rack to drain excess oil.
Assembly
Divide 2 portions cooked Japanese short-grain rice and 70 g green cabbage into serving bowls.
Place the karaage on top and drizzle with sauce (alternatively, you can cook the karaage in the sauce for a few minutes to cover it more thoroughly). Top with finely chopped green onions, red pickled ginger (benishoga), toasted white sesame seeds and chili threads.