Cut chicken breasts in half lengthwise. Flatten with a mallet to 1/4 inch thickness. Sprinkle with sansho pepper, salt and pepper. Place carrot and trefoil on top and roll up. Tie with string or skewer together. Saute the rolled up chicken in oil until browned on all sides. Mix soy sauce with the dashi and add to chicken. Lower heat and simmer for 10 minutes. Add drained mushrooms to chicken and simmer for 5 more minutes. Serve on a bed of rice and chais with the sauce poured over the top.