Rinse the rice in a fine mesh strainer until the water runs clear, eliminating excess starch. Combine the washed rice with 4 ½ cups of water in a large saucepan. Bring the mixture to a boil over high heat, stirring occasionally. Once boiling, lower the heat, cover, and allow the rice to simmer until the water is fully absorbed, about 15 to 20 minutes. Let the rice rest with the lid on for 15 minutes to finish steaming and achieve optimal tenderness. Cool the cooked rice before proceeding.

Mix the remaining 1 cup of water with the salt in a small bowl. Use this salted water to lightly moisten your hands before handling the rice, preventing it from sticking. Divide the cooled rice into 8 equal portions. Each portion will form the base of an onigiri.

For each onigiri, split a portion of rice into two. Create a small hollow in one half and place a generous teaspoon of bonito shavings inside. Cover the filling with the other half of the rice, pressing gently to enclose the filling securely within the rice ball. Shape the rice into a triangular form with gentle pressure, then wrap each onigiri with a strip of nori and sprinkle with sesame seeds. Repeat this process for the remaining rice portions.