Boil a small pot of water on high, once water is boiling add eggs and let eggs boil for 7 minutes.
Place eggs in an ice bath as soon as 7 minutes have past.
Combine all remaining egg ingredients in a bowl to create the marinade.
Peel eggs and place in a ziploc bag with the marinade. Try to remove any excess air from the bag, so that the marinade covers the eggs. Marinate for 2 to 6 hours.
Chasu Pork Belly
In a small sauce pan, heat up tamari, sake, mirin and sugar on medium heat until all sugar is dissolved.
Add scallions, garlic, and ginger and remove sauce pan from heat and let cool.
Place chasu in a vacuum seal bag or ziploc bag and pour marinade on top.
Remove any extra air from bag and sous vide for 36 hours at 63 celsius.
After 36 hours, slice chasu into ¼ inch slices. Heat cast iron to medium high heat and sear both sides of each piece of chasu.
Soup
In a large pot or InstantPot, heat tonkotsu broth up to a boil.
Stir in all remaining soup ingredients.
Assembly
Place noodles in a bowl and then ladle broth over the noodles until noodles are covered.
Lay slices of chasu on top of the noodles. Cut egg in half and place on top of noodles along with a piece of nori.
Garnish with green onions and a dash of togarashi.