Place kombu and water in a pot and let it sit for 30 minutes.

Prepare the mushrooms: separate maitake and shimeji into small clusters, trim enoki roots and loosen, and cut shiitake caps with shallow cross cuts. Mince shiitake stems. Prepare cabbage by cutting into bite-sized pieces, separating the core and leaves. Slice carrot into 5mm rounds and use a cutter for decorative shapes. Microwave carrot pieces with a little water for 40 seconds.

In a bowl, mix ground chicken, minced shiitake stems, minced carrot, and meatball seasoning ingredients until sticky.

Heat the pot with kombu water over medium heat. Remove kombu before boiling. Drop spoonfuls of meat mixture into the pot and simmer for 5 minutes on low heat until cooked.