Add the 400 g fresh noodles to the boiling water. Stir gently to prevent sticking and cook according to package guidance — typically 90 seconds to 3 minutes for fresh noodles. Taste after 90 seconds: noodles should be tender with a slight chew (al dente). Do not overcook.

Shock and drain

When cooked, reserve 120 ml of the cooking water then immediately drain the noodles in a fine-mesh strainer. If serving chilled, rinse briefly under cold running water. For hot soup, you can skip rinsing but toss noodles quickly with a teaspoon of neutral oil to prevent clumping if not serving immediately.

Broth (clear, umami-forward)

Prepare dashi

If using kombu + bonito: soak a 10 cm kombu strip in 1.2 L cold water for 30 minutes, then gently heat until just below simmering. Remove kombu and add 10–15 g bonito flakes. Simmer 30 seconds, remove from heat, let sit 2 minutes, then strain. If using instant dashi, dissolve to make 1.2 L stock.

Season the broth

Return the strained dashi to a clean pot over medium heat. Add 3 tablespoons light soy sauce, 2 tablespoons mirin, and 1 tablespoon sake. Stir and bring to a gentle simmer. Taste and add 1 teaspoon salt as needed. Keep broth hot but not boiling to preserve delicate flavors.

Finish with aromatic oil

Just before serving, whisk in 1 teaspoon toasted sesame oil for fragrance and 2 teaspoons neutral oil if you want a slight mouthfeel. Keep the broth at serving temperature (around 75–85°C).

Toppings (choose or combine as desired)

Prepare soft-boiled eggs (ajitsuke tamago)

Bring a small pot of water to a simmer. Gently lower 2 eggs and cook 6 to 6.5 minutes for runny yolks. Transfer to an ice bath for 5 minutes, peel carefully. (Optional) Marinate peeled eggs in a mix of 3 tablespoons soy sauce + 3 tablespoons mirin + 50 ml dashi or water for 2–6 hours or overnight for deeper flavor.

Heat or sear protein

If using chashu, warm slices in a skillet over low heat or briefly sear chicken slices: heat 1 teaspoon neutral oil in a pan over medium-high heat, sear meat 1–2 minutes per side until glazed and warmed through. Slice thinly.

Prepare vegetables and garnishes

Trim scallions: slice white parts thinly on the bias and finely slice green parts for garnish. Blanch 100 g spinach in boiling water for 30 seconds, then plunge into ice water and squeeze dry. Warm menma or marinated mushrooms in a small pan or microwave briefly. Toast sesame seeds if desired.

Assemble bowls

Divide cooked noodles among 4 bowls (about 100 g each cooked weight). Ladle hot broth over noodles, using reserved noodle cooking water to adjust temperature if needed. Arrange toppings: 1 soft-boiled egg halved per two servings (or 1 per person), 50 g sliced protein per bowl, a small handful of spinach, a spoonful of menma, scallion whites, and nori strips. Garnish with scallion greens, a sprinkle of sesame seeds, and a pinch of shichimi or a few drops of chili oil if desired.