Bring a small pot of water to a boil and cook the egg for 6.5 minutes, then immediately transfer to an ice bath to cool.
Cook the soba noodles in a separate pot of boiling water according to package directions, then drain and set aside.
In a large pot, heat the sesame oil over medium-high heat and brown the ground pork until fully cooked through.
Stir in the minced garlic and grated ginger, sautéing for 1 minute until the aromatics are fragrant.
Pour in the chicken broth, sriracha, tamari, sea salt, and black pepper, bringing the mixture to a gentle simmer.
Add the chopped bok choy to the broth and cook for 2-3 minutes until the leaves are wilted and the stems are tender.
Divide the cooked noodles into a large bowl, pour the pork and spicy broth over them, and top with the peeled, halved egg and sliced green onions.