What did the declassified documents reveal?

Cold Open: This is a declassified State Department Intelligence and Research Note, dated December 29, 1967, detailing US concerns about a possible Chinese nuclear test failure. The document, released through The Black Vault, suggests that the Chinese nuclear test on December 24 may not have been a success. Provenance: The document was released through a Freedom of Information Act request and is available on The Black Vault's website. The canonical PDF is located at https://archive.org/download/us-china-intel-CI01847/CI01847djvu.txt. The Document: To: The Secretary Through: S/S From: INR - George C. Denney, Jr. Subject: Chinese Nuclear Test May Have Been Failure Preliminary technical analysis of Communist China's seventh nuclear test, together with Peking's continuing silence about the event, suggests that the test could have been a failure. Thermonuclear Material Present. The test, which took place on December 24, 1967, in the vicinity of the nuclear test site at Lop Nor, had an estimated yield of 10 kilotons. Preliminary debris sampling has shown that lithium deuteride, thermonuclear fuel, was present in the device. The third, fifth, and sixth Chinese nuclear tests involved thermonuclear material, and their estimated yields were approximately 250 KT, 300 KT, and 3,000 KT, respectively. Given the thermonuclear material content and other technical evidence, the low yield of the seventh test suggests that something may have gone wrong during the detonation, and that the Chinese may have expected a yield of at least several hundred kilotons. However, we cannot exclude the possibility that the device was a 'mock-up' using some dummy components to replace the active materials, thus reducing the yield. Chinese Silent on Detonation. On balance, we believe the test was a failure. Contrary to their usual practice of announcing nuclear tests with great fanfare, Peking has yet to mention the December 24 detonation. This silence strengthens the impression that the test may not have gone according to plan. The timing of the detonation, moreover, could suggest that more than a 10 kiloton blast was produced. Context: The document suggests that the Chinese nuclear test was intended to coincide with Mao's birthday on December 26, and to counter the Soviet Union's 50th Anniversary celebrations. However, the low yield and Peking's silence about the event raise questions about the test's success. Outro: This is what the public record looks like at its most ordinary. The document, a declassified State Department Intelligence and Research Note, provides insight into US concerns about a possible Chinese nuclear test failure. The document is available on The Black Vault's website at https://archive.org/download/us-china-intel-CI01847/CI01847djvu.txt.

Why was this case declassified?

This material entered the public record through the U.S. declassification and Freedom of Information Act (FOIA) process. The originating source document is linked on this page so the citation chain is auditable.

State Department Intelligence And Research Note, Dated December 29, 1967

◆ BLUF — The short version

Cold Open: This is a declassified State Department Intelligence and Research Note, dated December 29, 1967, detailing US concerns about a possible Chinese nuclear test failure. The document, released through The Black Vault, suggests that the Chinese nuclear test on December 24 may not have been a success.

Date: AUG 13 · 2026
Release: Declassified · U.S. public record (FOIA)
Source document: View the primary source document

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What was State Department Intelligence And Research Note, Dated December 29, 1967 about?: Cold Open: This is a declassified State Department Intelligence and Research Note, dated December 29, 1967, detailing US concerns about a possible Chinese nuclear test failure. The document, released through The Black Vault, suggests that the Chinese nuclear test on December 24 may not have been a success.
Why was this case declassified?: This material entered the public record through the U.S. declassification and Freedom of Information Act (FOIA) process. Storyflo narrates it directly from the public release.

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State Department Intelligence And Research Note, Dated December 29, 1967

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