Cut chicken thigh into bite-size pieces
Combine soy sauce, Sho Chiku Bai classic Junmai Sake, Takara Mirin, grated ginger and grated garlic in a medium bowl or directly into a plastic bag. Then, add the chicken pieces from step 1
Let chicken marinated in refrigerator for 1 hour or over-night. If you are using a plastic bag, make sure to remove as much air as possible before closing the bag, so the liquid covers all of the chicken
Heat oil to 350°F in a deep pot. A regular frying pan will work also
In a tray spread potato starch and coat chicken. Shake off excess. The amount of chicken here should be determined by how much of it can fit in the pot at one time. Always coat chicken with potato starch right before it goes into the frying oil
If you marinated the chicken in a plastic bag, you can always add the potato starch directly to the bag and shake to coat the meat
Fry chicken in 350°F oil for 3 minutes, turning it once after 1.5 minutes. Remove chicken from oil and set aside for 3 minutes (meat will continuously cook)
Lastly, place chicken back in 350°F oil for 1 minute