Taiwan has finished testing its land-based Harpoon anti-ship missiles, a boost for the island's ability to defend the waters around it and a new headache for China's navy.

• The truck-mounted Harpoon batteries have cleared their test phase and are set to join Taiwan's coastal defenses.
• The missiles are meant to hit warships from land, so Taiwan can strike an invasion fleet without risking its own ships.
• Mobile launchers are hard to find and destroy, which makes them survivable if a conflict starts.
• The system is a core piece of Taiwan's shift toward cheaper, harder-to-kill weapons instead of big-ticket platforms.
• It also deepens Taiwan's military reliance on American-supplied hardware at a tense moment across the strait.

Outlook: Expect the batteries to move into service and China to protest the deliveries, with more US arms packages likely to follow.