Cut the chicken into thin round slices, and season with salt. Rub in some sake and let it sit. Finely chop the leek.
Lightly coat the chicken from Step 1 in flour. Heat a thin layer of vegetable oil in the frying pan and fry the chicken until both sides have browned. Since they will be simmered later, it's okay if they aren't cooked all the way through.
Remove the cooked chicken and wash the frying pan. Then add the dashi, soy sauce, vinegar, and sugar to the cleaned frying pan and turn on the heat. Once it comes to a boil, add in the cooked chicken.
Cover with a lid and let it simmer over medium heat. When the liquid has evaporated, turn off the heat. Add in all of the leek and roughly mix it in to finish.
Story Behind this Recipe
I wanted to come up with a good way of cooking chicken breast meat that wouldn't dry out.
You can make this with chicken thighs. Adjust the amount of vinegar to taste.