Gather all the ingredients. Bring a large pot of water to boil for cooking noodles (Don't cook yet till Step 5). In a medium saucepan, add dashi, mirin, and sugar. Add soy sauce and kosher salt and bring to boil. Once boiling, turn off the heat and set aside. Squeeze excess liquid from the inariage (or you can keep it as it is). Cut the green onion into thin slices. Slice the Narutomaki fish cake into 1/8 inch (3 mm). When everything is ready, start cooking udon noodles. Frozen udon noodles (my favorite kind) takes only 1 minute from putting into boiling water. If you use dry noodles, follow the package instructions. Heat up the noodle soup. Pick up the noodles in a strainer or drain hot water. Make sure to remove excess water (which will end up diluting your soup). Serve udon noodles and soup in serving bowls and top with inariage, narutomaki, green onion and sprinkles of shichimi togarashi.