To make the sauce,
Return to the soy sauce in a pan, add the rest of the sauce ingredients. Mix well. Add a little more water if you prefer your sauce thinner.
To cook noodles, boil water in a pot and add noodles and cook according to package directions. Stir often so they don't stick together. Drain and rinse the noodles with very cold water.
To serve, place desired amount of noodles in a large bowl and top with 2-3 tablespoonful of sauce, place cucumber and radish slices on top, and top with boiled egg half.
Cut noodles with a pair of scissor 2-3 times and mix well with sauce and toppings. Enjoy..