Nice, light, and chilled for a hot summer day when you don't feel like eating anything that's hot and heavy. Not piled with annoying flavor either, just simple and refreshing. By the way, actual prep & cooking time depends on how used to making it you are and what all extras you want to add. Enjoy.
Put water in a saucepan with ginger and heat to almost a boil. Get a bigger pot ready to boil the noodles.
Add soy sauce, rice vinegar, and fish stock. Keep on medium-low heat for about 7 min.
Remove soup from heat and put it in the refrigerator until the noodles are done. This will help with the cooling a bit.
Bring water in the bigger pot to a boil and add the noodles. Keep on medium-high for 2 1/2 min.
Remove the noodles from heat and run them under cold water in a mesh strainer until you don't feel any hot water coming out the bottom.
Put desired amount of noodles and soup in two separate bowls. You can put an ice cube or two in the soup if it's still hot. After a few rounds of noodles it'll be chilled anyway, if you don't want to dilute it with the ice. Add whatever toppings you'd like to the soup with some of the noodles and there you have it. For topping examples, I usually like fresh green onions, shaved tuna flakes, spinach, various tempura items, but you can put whatever you want on it. Some people like it plain without anything extra.