Japanese mixed rice -- "Takikomigohan"

Do you like rice and soy sauce? If so, you will be satisfied with a bowl of this mixed rice. In Japan, this dish is usually served in the Fall. But I eat throughout the year.
Here is the way I made.

Ingredients:
4 servers

1 1/2 cups Japanese rice, washed and drained in a colander about 30 minutes
11 oz (300 g) boneless skinless chicken thigh, cut into small pieces
1 pack shimeji mushroom, removed stems, washed and drained
1/2 carrot, peeled and shredded thinly
Kombu about 2 inch
1 tbsp sake
2 tbsp mirin
2 tbsp soy sauce
1 tbsp vegetable oil

Method:

1) Wash kombu under running faucet or wipe away dirt with a wet clean towel. Combine kombu, 1 cup water, sake, mirin, soy sauce in a small sauce pan. Bring to a boil. Discard the kombu.

2) Heat a large skillet over moderately high heat, add oil, swirling to coat, then stir-fry chicken until golden in places. Add carrot, mushroom, continue to stir-fry about 1 minute.

3) Transfer stir-fried chicken veges mixture into kombu soup. Bring the mixture back to a simmer about 5 minutes, skimming off any foam or impurities that rise to the surface. Remove from the heat. Cover and steep for 30 minutes or overnight.

4) Use a colander with a bowl underneath, remove the soup from the pot. Add more water in the soup to make 2 cups of liquid. Place washed rice in rice cooker and pour the liquid over the rice. Start cooking the rice.

5) When it's done, mix the chicken veges mixture into the rice, keep covered for about 10 minutes.
Put into small bowls and serve warm.