Chinese coast guard vessels pushed into waters around Taiwan's Kinmen islands twice on Monday, a further sign that pressure on Taiwan's front-line islands is rising.

• Four Chinese coast guard ships crossed into Kinmen's restricted waters in the morning, were driven off, then came back in the afternoon.
• On the second run they split into eastern and western groups, apparently to stretch Taiwan's response thin and test how it reacts.
• Taiwan's coast guard shadowed each ship one-on-one and used radio in Chinese and English to order them out; all left by late afternoon.
• Taipei calls this "gray zone" pressure — harassment kept just below the level that would count as an attack.

Outlook: These incursions have become routine and are likely to continue, with Taiwan holding to its "no avoidance, no retreat" line.