Wash the rice well and drain. In a rice cooker, add washed rice and 2 ½ cups of water. Let the rice soak in the water, about 15-30 minutes. Cook the rice according to your rice cooker.
Mix the bonito flakes with soy sauce. Set it aside.
When the rice is cooked, fluff the rice with shamoji (wooden spoon) and divide the rice roughly into 8-10. Keep the rice hot.
Set the working station with cooked rice, a bowl of water, an empty rice bowl, a small bowl of sea salt, bonito/ soy mixture, plum paste, and a plate large enough to hold all the rice balls.
Scoop ⅛ (or 1/10) of the rice into the empty rice bowl. Make an indentation in the middle. Place pickled plum or bonito.
Moist both of our hands, and apply small amounts of salt (approximately ½ teaspoon) to your hand. Transfer the rice from the rice bowl on to moist hands and gently form the rice into a triangle shape. Place it on a plate and continue making until all the rice is formed into onigiri.
Wrap each onigiri with one strip of Nori. Enjoy.