Taiwan has flown one of its new American-made MQ-9B surveillance drones for the first time, a clear boost for its ability to watch the seas and skies around the island.

• Two of four MQ-9B Sea Guardian drones bought from the US arrived in June and flew their first test from Hualien air base, landing safely after two hours.
• The drones can stay airborne for a full day or more and cover the Taiwan Strait plus parts of the Bashi and Miyako channels from a single orbit.
• They carry both sensors and weapons, including laser-guided bombs, and the US has already tested fitting them with air-to-air missiles.
• The main job is watching Chinese navy and coast guard ships that press against Taiwan in the grey zone below outright war.
• Linked into the Link-16 data network, they let Taiwan share targets faster and build what amounts to a surveillance wall along the first island chain.

Outlook: The remaining drones are due next year, extending Taiwan's watch further out to sea and toward the Chinese mainland.