• Gather all the ingredients.
  

To Make the Teriyaki Marinade

• Grate the ginger (I use this grater) and add ½ tsp ginger (grated, with juice) to a large bowl. Next, grate ¼ onion into the bowl.
  
• To the same bowl, add the teriyaki sauce ingredients: 1 Tbsp sake, 1 Tbsp mirin, 1 Tbsp sugar, 2 Tbsp soy sauce, and 2 Tbsp water. Mix together well.
  

To Prepare the Chicken

• Prick both sides of 1 lb boneless, skin-on chicken thighs with a fork so it absorbs more flavor. If the thighs are very thick on one side, flatten them to an even thickness with a meat mallet/tenderizer.
  
• Cut off the excess skin and fat and lightly season the chicken pieces with Diamond Crystal kosher salt and freshly ground black pepper.
  
• At this point, you either can go straight to cooking the chicken or marinate it for 30 minutes (optional). In Japan, we don’t usually marinate the chicken prior to pan-frying, as the sauce can easily burn. Today, I’ll show you how to marinate the chicken and cook it to highlight key points to follow when using this optional method. To marinate, place the chicken pieces in the bowl with the teriyaki marinade and coat well. Let sit for 30 minutes.
  

To Cook the Teriyaki Chicken

• Heat a large frying pan over medium heat. When the pan is hot, add 1 Tbsp neutral oil. Remove as much of the marinade as possible from the chicken so it gets a nice sear and doesn‘t end up steaming in the sauce. Place the chicken skin side down in the pan; reserve the teriyaki marinade. Use a splatter screen if you have one to prevent oil splatters.
  
• Cook the chicken for 3 minutes. When the fat renders from the skin and the skin is golden brown, flip the chicken. Add 2 Tbsp sake to the pan and quickly cover with a lid. Steam the chicken over medium-low heat for 8 minutes.
  
• Open the lid and transfer the chicken to a plate. Wipe off the excess grease from the pan with a paper towel.
  
• Put the pan back on the stove over medium heat and add 1 tsp neutral oil. Place the chicken back in the pan, skin side down. Brown and crisp the skin for an additional minute.
  
• Flip the chicken so it‘s now skin side up. Pour the reserved teriyaki marinade into the pan. Cook until the sauce is reduced by about half, frequently spooning it over the chicken. Once the alcohol from the sake and mirin evaporates, you‘ll see the sugar start to crystallize and the sauce thicken. Turn off the heat.
  
• Transfer the chicken to a cutting board and slice into bite-sized pieces. 
  
• Serve on a plate and drizzle the remaining pan sauce on top.
  

To Store

• You can keep the leftovers in an airtight container and store in the refrigerator for 3 days or in the freezer for a month.