In a bowl combine the water, vinegar and burdock root. Let it the burdock root sit in the water for about 10 minutes. Place a pan over medium-high heat and saute the burdock root and carrots for 5 minutes.

Add the chicken thighs and cook for 5 minutes, or until all the chicken has turned white.

In a small bowl combine the soy sauce, fish sauce, salt, and mirin. Pour into the pan with the chicken and mix together. Cook until the sauce has been absorbed or until the chicken is thoroughly cooked.

Combine the chicken mixture with the sushi rice.

Time to shape the onigiri. Have a small bowl of water next to you because you are going to want to keep your hands moist. Wet your hands and then take a hand full of the rice mixture and begin forming triangle shapes. Put a moderate amount of pressure to make sure they are forming correctly.