Chopped scallion into small pieces (if you have some)
Boil the water in a pot.
Peel the daikon. Right over from the pot, slice the daikon into thin round slices with a slicer.
When the water gets boiled, turn the heat off (the daikon should be cooked by then). Dissolve in the dashi stock granules and miso, sprinkle the chopped scallion, and it is done.
There is also a recipe of thinly sliced daikon, "Quick Nabe Dish with Daikon and Pork"
Recipe ID: 1283324
There is also a recipe for easy miso soup, "Easy Miso Soup with Lots of Wakame Seaweed with the Microwave" Recipe ID: 1305044
Story Behind this Recipe
I'm too lazy to use a chopping board and knife and I do not have enough time, and do not want to waste the cost of fuel and light. Also my kids do not eat thick daikon slices, but I have many of daikon, so...
It's ok to cut the daikon just into round slices, but if you cut it lengthwise into 4 pieces, and slice the daikon by a slicer, they'll look and taste like dried gourd shavings. Our miso soup is rather light, adjust the seasoning as you like.