This question involves finding craftsmen who make hidden weapons, which sounds like a scene in fiction or ancient martial arts novels. In reality, it is usually illegal to make hidden weapons. If this is for: -Create a novel or game plot, you can set such a craftsman in a remote village, an ancient family or a secret organization -For historical research, you can check the historical materials of ancient Chinese weapons or visit traditional craftsmanship protection agencies -For the production of performance props, you should consult a professional props production company and ensure compliance with local regulations. If you are interested in traditional crafts, you can legally explore the study and collection of traditional iron and wood crafts. Please make sure your interests are within the scope permitted by law.