Cut mizuna into 3cm pieces, soak in water for 5 minutes, and drain. Slice daikon into 5mm thickness. Mince green onion.

In a plastic bag, combine ground chicken, minced green onion, and seasoning ingredients. Knead the mixture through the bag until sticky. Cut the tip of the bag.

Layer daikon slices and chicken mixture alternately in a heatproof dish, forming a radial pattern. Repeat until ingredients are used up.

Drizzle sake over the layered dish, cover loosely with plastic wrap, and microwave at 600W for 7 minutes. Let it sit for 1 minute with the wrap on.