Cut the kombu into 3 cm pieces. Place the kombu and water in a pot and soak for 1 hour.

Cut the salted salmon into bite-sized pieces. Place it in a heat-resistant container with a strainer and pour hot water over it briefly to remove excess salt. Drain well.

Cut the daikon and carrot into thin slices after quartering them lengthwise. Cut the potato into 1 cm slices after quartering lengthwise. Soak the potato slices in water, then drain.

Heat the pot with kombu on low heat to extract umami. Once small bubbles form around the edges, remove the kombu. Add the daikon, carrot, and potato, mix briefly, and bring to a boil over medium heat. Cover and simmer on low heat for 5 minutes.