Slice the green onion into small pieces.

Crack 3 eggs into a bowl and whisk them well.

Drain the oil from the tuna can completely.

Prepare 1L of broth for the soup.

Bring the broth to a boil and add 1 tbsp minced garlic.

Add the drained tuna to the boiling broth.

Add the sliced green onion to the soup.

Add 1 tbsp mirin to the soup.

Season the soup with 1 tbsp soy sauce.

Add 0.1 tbsp salt to the soup.

Sprinkle 0.1 tbsp pepper into the soup.

Pour the whisked eggs into the soup.

Let the eggs cook until they form soft clumps, then gently stir.