Cut napa cabbage into bite-sized pieces, separating the core and leaves. Slice the green onion diagonally into 1.5cm pieces. Trim the root of the shimeji mushrooms and separate them into small clusters.

Cut the mochi in half.

Pat the fried tofu with a paper towel to remove excess oil. Roll with a chopstick to flatten slightly, then cut in half. Open each piece and insert a mochi piece, securing with a toothpick to create 4 mochi pouches.

Trim excess fat from the chicken thigh and cut into bite-sized pieces.

In a pot, combine the soup base ingredients (sake, mirin, water, garlic, ginger) and heat over medium heat. Once boiling, add the chicken pieces, cover, and simmer on low heat for 7 minutes. Dissolve the miso into the soup.

Add the cabbage core, green onion, shimeji mushrooms, and mochi pouches to the pot. Cover and simmer for 5 minutes.