Make the sauce by heating the oil in a large pan and gently sautéing the onion until soft and translucent. Add the carrot, celery, garlic and ginger and cook for five minutes until soft.
Stir in the curry powder, season well and add the tomato purée. Cook for a couple of minutes. Add the flour and stir well. This will thicken the sauce.
Pour in the stock and bay leaf, bring to the boil and simmer for ten to fifteen minutes, until thickened. Add the honey, vinegar, mirin and soy sauce and check for balance. It should be slightly fruity with a little tang. Keep warm.
Cook the rice in the Hijiki water, having removed the seaweed. When ready, stir through the seaweed and adjust the seasoning.
Cook the chicken according to the instructions and serve sliced with the rice and sauce.