Chicken Zosui (Japanese Rice Soup)

Name: Chicken Zosui (Japanese Rice Soup)
Prep time: 10 min
Cook time: 30 min
Total time: 40 min
Cuisine: Japanese
Ingredients: 150 g boneless chicken thigh(s) (skin-on, boneless); 1 tsp cooking oil; 1 pinch black pepper; 400 ml dashi stock; 1 tbsp sake; 200 g cooked Japanese short-grain rice; 30 g green onion(s) (white part diagonally sliced); 80 g carrot(s) (julienned); 2 fresh shiitake mushroom(s) (thinly sliced); 100 g enoki mushroom(s) ( roots removed); 15 g fresh ginger ( grated); 3 tbsp light soy sauce (see note for how to use dark soy sauce); 2 medium egg(s); finely chopped green onion(s) (optional garnish); shredded sushi nori seaweed "kizami nori" ((kizami nori) option garnish); Japanese chili powder ( (shichimi togarashi) optional garnish); sesame oil (optional garnish)