The drill is to prep for humanitarian search-and-rescue work that backs up a longstanding mission of the coast guard on Taiping Island. The islet with a clinic and lodging is supposed to be a place where people from any country can go when in trouble, say because of a storm at sea. Taiwan wants the other claimants to remember its claim. But it also wants to be seen as an advocate of peaceful cooperation rather than aggression.

“Really the whole idea of turning it into a search and rescue hub is kind of just the next step in that whole approach to in the peace effort,” says Jonathan Spangler, director of Taipei-based South China Sea Think Tank.