Security experts warn that China could choke off shipping around Taiwan without firing a shot, a risk that would hurt Taiwan, Japan, South Korea and the global economy.

• Retired British Royal Navy Vice Admiral Duncan Potts said Taiwan's goal should be making sure Beijing never decides the risk of acting is worth taking.
• A Chinese "quarantine" could start small: coast guard ships issuing warnings, declaring drill zones, then boarding cargo ships for inspections.
• Just a few inspections would be enough to spook shipping firms and insurers, pushing them to avoid the Taiwan Strait entirely.
• China's pipelines to Russia, Pakistan and Myanmar mean it could survive a sea blockade while Japan, Taiwan and South Korea could not.
• Xi Jinping is building a combined civilian-military maritime system to control shipping rules, and new underwater enforcement moves are expected.

Outlook: Expect more Chinese grey-zone pressure at sea, with Taiwan, Japan, South Korea and the US pushed toward joint planning to keep shipping lanes open.