Zaru Udon (Cold Udon Noodles with Dipping Sauce)

Combine the ingredients for the dipping sauce (dashi stock, mirin, soy sauce, and sugar) in a pot and bring it to a boil over medium heat. Once boiling, reduce the heat to low and let it simmer for about 30 seconds before removing it from the heat. After it cools down, transfer the sauce to a container (or leave it in the pot) and chill it in the refrigerator.
If using fresh, dried, or pre-cooked udon noodles: Boil the udon noodles according to the package instructions.
If using frozen udon noodles: Lightly sprinkle water over the udon noodles. Then, place them on a microwave-safe plate, cover with plastic wrap, and microwave on medium power (500W) for about 4 minutes. (Since this method can cause uneven heating, it is best to microwave one serving at a time. You can also boil them like the other types of udon noodles.)
Drain the noodles in a colander, then rinse them under running water or submerge them in ice water to cool them. Once cooled, drain off any excess water.
Place a dish or tray under the strainer to catch any water dripping from the noodles. Fill small serving bowls with the chilled dipping sauce. Arrange the condiments on a separate plate based on personal preferences.