Mix the Egg Base: In a bowl, use chopsticks to gently slice through the eggs to break the yolks and mix them with the whites. Do not whisk aggressively, to avoid creating foamy air bubbles. Gently stir in the dashi stock, light soy sauce, mirin, and salt.

Prepare the Pan: Heat a rectangular Japanese tamagoyaki pan over medium-low heat. Fold a piece of paper towel, dip it in vegetable oil, and coat the entire pan thoroughly.

First Layer: Pour a thin, even layer of the very liquid egg mixture into the pan. As soon as the bottom sets but the top is still wet and runny, roll the egg tightly from the front of the pan to the back. Push the rolled egg to the front of the pan.

Continue Layering: Re-oil the empty pan using the paper towel. Pour another thin layer of egg, lifting the first roll slightly so the new liquid flows completely underneath it. Roll the egg back over the new layer.

Finish and Serve: Repeat the pouring, lifting, and rolling process 4 or 5 times until all the egg mixture is used and a thick, rectangular block is formed. Remove from the pan, slice cleanly into thick pieces, and serve immediately alongside a mound of freshly grated daikon radish.