Combine the soy sauce broth ingredients in a saucepan, bring to a simmer, and remove from the heat. Let it cool.
Bring a large pot of water to a boil, add the udon noodles and cook according to the directions on the package. Drain the noodle and place immediately under cold running water to halt cooking. Drain well and put in a serving bowl.
Mix broth and yuzu pepper paste and stir well to melt.
Arrange the all herbs and greens, vegetables on top of the noodle. Pour the cold broth over the noodle just before eating.