1/3 cup soy sauce, more to taste (I like low-sodium soy sauce.)
1/3 cup ketchup or 3 tablespoons tomato paste and a pinch of sugar. (I used tomato paste and sugar; it was fine.)
1 tablespoon rice wine vinegar, more to taste. (You could use white vinegar and brown sugar.)
A few drops dark sesame oil ( optional) ( I didn't have any.)
A squirt of sriracha or other sauce, or a dried red chili to taste (optional) (I used red pepper flakes.)
1 pound egg noodles, preferably fresh. (I used packaged noodles.)
1. Bring a large pot of water to a boil and salt it. In a smaller pot, bring 6 cups of water to a boil; once boiling , reduce heat so water bubbles gently.
2. To the smaller pot add soy sauce, ketchup (or tomato paste and sugar), vinegar, sesame oil if using and sriracha or chile, along with pinch of salt. Stir and let simmer.
3. Add egg noodles to large pot. When tender but not mushy, drain. Add more soy, salt, vinegar to taste.