Prepare Rice: Rinse 1 cup of sushi rice until water runs clear, then cook according to manufacturer instructions (about 20 minutes). Transfer to a bowl, sprinkle with salt and optional furikake, folding gently while cooling.

Marinate Chicken: Slice 1 pound of chicken, mix with soy sauce, sake, baking soda, and cornstarch. Marinate in the fridge for at least 30 minutes.

Make Teriyaki Sauce: In a saucepan, combine 1/4 cup soy sauce, 2 tablespoons mirin, and 2 tablespoons brown sugar. Whisk over medium heat until smooth (2-3 minutes), then remove from heat and cool slightly.

Cook Chicken: Heat 1 tablespoon of oil in a skillet over medium-high heat. Cook marinated chicken for 2-3 minutes until golden brown. Stir in 1 teaspoon of minced garlic for the last 30 seconds. Pour in teriyaki sauce, stirring for 1-2 minutes until thickened.

Shape Onigiri: Wet hands and grab a handful of sushi rice. Mold into a triangle, fill with chicken mixture, fold rice over filling and press to seal.

Wrap with Nori: Cut nori into strips and wrap around each onigiri, leaving the top exposed for presentation.