Boil water in a large pot and add soba noodles. Do not add salt to water. Cook according to package directions stirring regularly to ensure they don’t stick together. Before draining, reserve one to 1 ½ cups water and set aside.
Drain noodles and rinse with cold water.
Transfer noodles to a large bowl of ice water so they cool completely.
Place a bamboo mat or sieve over a plate to serve. The plate will catch the water from the noodles. Put soba noodles on the mat and garnish with nori.
To serve the dish, combine 6 tbsp. water with about 1 ¼ cup dipping sauce. (This will get you the 3:1 ratio). If it’s too salty, add more water. If it’s too thin, add more sauce.
Put chopped green onions and wasabi on a small plate and serve with the noodles.