Newly released Chiang Kai-shek diaries show the US pressured Taiwan to abandon the Dachen Islands in 1955, leaving Chiang feeling betrayed over promises to defend Kinmen and Matsu.

• Taiwan's national archives opened a new batch of Chiang Kai-shek and Chiang Ching-kuo diaries covering 1955–1957 and 1961–1963.
• During the first Taiwan Strait crisis, Washington offered to help defend Kinmen in exchange for Taiwan pulling out of the Dachen Islands.
• Chiang later accused Eisenhower of breaking that promise and pushing him to give up Kinmen too, calling him repeatedly untrustworthy.
• The diaries also cover the 1957 riot that wrecked the US embassy in Taipei after an American sergeant was acquitted of killing a Taiwanese man.
• Chiang Ching-kuo's entries show heavy US pressure at the UN over Outer Mongolia's admission, which Taiwan ultimately answered by walking out of the vote.

Outlook: More batches are due each quarter, and each release adds detail to how much Taiwan's security has always hinged on shifting US commitments.