Mix Soy Sauce, sugar, and rice vinegar in a large bowl, and set aside.
Boil water in a medium pot.
Meanwhile, slice Gobo thinly diagonally. Then cut into thin match sticks. Soak cut Gobo in water.
Cut carrot thinly too.
Drain water from the cut Gogo, add the Gobo to boiling water, and cook for 2 minutes. Add carrot and cook 1 minute longer. Strain the vegetables, add to the sauce, and mix well. Cool completely.
Then add mayo and sesame seeds and mix. Sprinkle with Shichimi pepper if you like.