Boil an egg for 8 minutes, transfer it to cold water, then peel.

Bring a pot of water to a boil, add a little extra water to lower the temperature slightly, and gently cook the pork slices until just done.

In a heatproof bowl, combine the soy sauce, mirin, and lemon juice. Microwave for 1 minute, pour the sauce over the cooked pork, and chill in the refrigerator.

Cut the egg in half, grate the daikon radish and squeeze out the excess moisture using a tea strainer or your hands, and chop the green onion.

Boil the frozen udon noodles according to the package directions, rinse thoroughly under cold water, and drain well.

Arrange the chilled noodles in a bowl and top with the pork, grated daikon, egg, and green onion. Drizzle the chilled sauce over everything and serve immediately.