Add the water, carrot and nappa cabbage in a clay pot. Cover with a lid and bring to boil over high heat.
Meanwhile, remove excess water from the cod using a paper towel. Turn down the heat and add the cod. Cook until the cod is half cooked.
Add the udon and cook for 1 and a half to 2 minutes. As an option, you could pre-boil the udon in boiling water in a medium pot and wash under running water to remove preservatives for better flavor.
Stir in the soup seasoning before turning off the heat.
Garnish with the green onion and sprinkle shichimi pepper. Enjoy!