Bring the chicken broth to a simmer in a large pot over medium-high heat, then stir in the minced garlic and grated ginger and cook for 5 minutes, until fragrant. Keep the liquid at a steady gentle simmer with small bubbles around the edges.

Stir in the soy sauce, sesame oil, and rice vinegar and taste, adjusting as needed. The broth should turn lightly amber-brown and smell savory with a mild tang.

Add the thinly sliced chicken and sliced shiitake mushrooms to the broth, then simmer for 10 to 12 minutes until the chicken is cooked through. Visual cue: the chicken pieces turn opaque and the mushrooms soften without breaking apart.

Cook the thin Chinese wheat noodles (or rice noodles) separately according to the package directions, then drain and divide them into serving bowls. The noodles should be tender and slippery, not clumped; rinse only if the package directs it.

Add the chopped bok choy to the soup and cook for 3 minutes until wilted. Visual cue: bok choy should turn bright green and become tender while still holding shape.

Ladle the hot soup over the noodles, then season with white pepper and salt to taste. Add until the noodles are fully covered and the broth looks clear and lightly glossy.

Top each bowl with sliced green onions, cilantro, and a drizzle of chili oil. Finish with a fresh, green garnish that sits on the surface and a small red chili oil sheen.