1. Wipe the shiitake mushrooms with a damp paper towel and then soak them in 2 cups of boiling water for at least 30 minutes. 2.Trim any excess fat or skin of the chicken thigh, leaving some behind (fat = flavor). Cut the chicken into 1/3-inch (1cm) cubes mix together with the soy sauce and mirin. Let this marinate for at least 20 minutes. 3.Put the rice into a fine mesh sieve and wash with your hand until the water runs clear. Let the rice drain well and then put it in a heavy bottomed pot with a tight fitting lid such as a dutch oven. 4.Add 1 3/4 cups of the soaking liquid from the shiitake mushrooms to the rice, and let this soak while you prepare the other vegetables (if you are using brown rice, you'll want to soak the rice for at least 1 hour). 5.Heat a sauté pan until hot and then add the oil. Keeping the marinade in the bowl, add the chicken into the hot pan in a single layer. Fry until well browned on one side, and then stir-fry. 6.Add the vegetables along with the remaining marinade and fry, string periodically until the vegetables are browned and there is no liquid left. 7.Dump the vegetables and chicken over the rice, but do not stir (if you mix it together the rice will not cook evenly). 8.Bring the pot to a boil over high heat. 9.Cover with a lid and turn the heat down to medium low and set the timer for 15 minutes. Do not open the lid while the rice is cooking or steaming. 10.Turn off the heat and without opening the lid, let the rice steam for 10-15 minutes. 11.When the rice is done steaming, mix it all together using a rice paddle and serve, garnished with minced scallions.