Rinse kiriboshi daikon thoroughly with water, squeeze out excess moisture, and cut into bite-sized lengths using kitchen scissors. Trim the root of shimeji mushrooms and separate them into smaller pieces.

In a pot, combine kiriboshi daikon, shimeji mushrooms, water, and dashi powder. Heat over medium heat until boiling, then simmer on low heat for 3–4 minutes until the kiriboshi daikon softens.