I want to know the answer to the following question:
When did the Hongwu Emperor use military force in Tibet?
All the background I'm provided with is that "Wang and Nyima state that, despite the fact that the Ming refrained from sending troops to subdue Tibet and refrained from garrisoning Ming troops there, these measures were unnecessary so long as the Ming court upheld close ties with Tibetan vassals and their forces.". Is that enough to answer the question?