Step 1

Cut the chicken into large bite-sized pieces and marinate with the soy sauce, sake, and grated ginger. It's best to let the chicken marinate for a few hours.

Step 2

To prepare the vegetables, cut the eggplant, sweet potato, and carrot into an oblique cut by slicing bite-sized pieces off at a 45° angle and then rotating the ingredient a quarter turn between each cut.

Step 3

Peel and slice the lotus root into 1/4-inch thick rounds and soak them in water acidified with lemon juice or vinegar.

Step 4

Remove the seeds and membranes from the peppers and cut them into squares.

Step 5

Preheat 1-inch vegetable oil in a high-sided pot to 340°F (170°C). Prepare a cooling rack by lining it with a few sheets of paper towels.

Step 6

Drain the lotus root and dry them well with paper towels. Dust all of the vegetables except the peppers in a thin layer of potato starch.

Step 7

Fry the vegetables one at a time. The peppers take about 20 seconds, the eggplant will take about 1.5-2 minutes, the lotus root will take about 1 minute, and the sweet potatoes and carrots will take about 3-4 minutes. Drain the vegetables on the paper towel-lined rack as they cook.

Step 8

To fry the chicken, dust them in a thick coating of potato starch and then fry them for about 4-5 minutes until they're golden brown and crisp. Drain the chicken on the paper towel-lined rack as well.

Step 9

To make the sweet and sour sauce, add the sugar, sake, and soy sauce to a 12-inch frying pan and bring the mixture to a boil.

Step 10

Once the sugar has dissolved and it no longer smells like alcohol, add the black vinegar, rice vinegar, and fried chicken and vegetables to the pan.

Step 11

Toss everything together to glaze with the sauce. Once the black vinegar sauce has thickened and coated everything, serve the Japanese sweet and sour chicken with rice.