Four eggs should be cracked into a bowl and whisked lightly back and forth using chopsticks. Don't whisk in a circular motion to separate the yolks and whites. Beat eggs gently.
Make the dashi stock according to package instructions.
In a separate bowl, add dashi, mirin, soy sauce, sugar, and salt. Mix well until all the ingredients are dissolved.
Heat the tamagoyaki pan on medium-high heat. Add 1 tsp of cooking oil.
You can use a greased paper towel or brush to spread the oil around in the pan.
Pour in about a quarter of the egg mixture to form a thin layer. Be sure the bottom of the pan is fully coated and pop any air bubbles that form.
When the omelette seems to be cooked halfway, begin rolling the layer of egg from the back towards yourself.
Keep rolling until the omelette is rolled to the edge of the pan.
Once done, transfer the omelette to the sushi mat. Press and roll the egg to give it the classic Japanese rolled omelette shape.
Next, cut the omelette into 1 inch pieces and grate some daikon radish on top as garnish.