What did the declassified documents reveal?

This is a declassified National Security Agency record concerning the Chinese hydrogen bomb test, dated June twenty‑seventh, nineteen sixty‑seven. The cable, identified in the archive as a United States intelligence assessment, is notable for its technical analysis of the explosion and its strategic implications for U.S. policy. The document was released to the public through The Black Vault. It was made available as part of a Freedom of Information Act request, declassified by the National Security Agency and posted on the archive site on June twenty‑seventh, twenty twenty‑two. The release includes the full text of the original cable, preserving its original classification markings. The cable begins with the heading “SECRET” and lists the originating office as the Department of State, routed through the embassies in Paris, Bonn, and London. The subject line reads: “Chinese H‑Bomb.” The body of the document states: “Peking announced that China’s first hydrogen bomb was successfully exploded in the air over western China on June seventeenth, nineteen sixty‑seven. This was the sixth Chinese‑Communist nuclear test, conducted less than three years after the first fission device. Our monitoring stations detected the explosion. We estimate that the device, which exploded in the vicinity of the Chinese nuclear test site at Lop Nor, had a yield between two and seven megatons. The burst altitude was between nine thousand five hundred and twelve thousand five hundred feet. We believe the device was dropped from a bomber aircraft. It appears that the bulk of the debris from the explosion rose above thirty thousand feet. Under the prevailing atmospheric conditions the upper‑air movements were relatively stagnant or drifting toward the west. Detonation time is compatible with our earlier estimates of the general pattern of Chinese Communist nuclear developments. As we indicated more than a year and a half ago, we believe that Communist China can produce during nineteen sixty‑six and nineteen sixty‑seven enough fissionable material to conduct a continued test program and, in addition, to stockpile a small number of nuclear weapons. The Chinese also appear to be making an intensive effort to develop operational medium‑range ballistic missiles and, apparently, work is under way on intercontinental‑range ballistic missiles. We can expect to see considerable activity toward the development of these missiles during the remainder of this year and the next few years. On the basis of recent evidence, it appears possible that they could conduct either a space or a long‑range ballistic missile launch before the end of nineteen sixty‑seven. If they give their intercontinental ballistic missile program a very high priority, they would still have to engage in extensive flight testing for three to four years before they would be able to deploy an operational ICBM by the early nineteen seventies

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.

National Security Agency Record Concerning The Chinese Hydrogen Bomb Test

◆ BLUF — The short version

This is a declassified National Security Agency record concerning the Chinese hydrogen bomb test, dated June twenty‑seventh, nineteen sixty‑seven. S. policy. The document was released to the public through The Black Vault.

Date: AUG 15 · 2026
Release: Declassified · U.S. public record (FOIA)
Source document: View the primary source document

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Episode notes

This is a declassified National Security Agency record concerning the Chinese hydrogen bomb test, dated June twenty‑seventh, nineteen sixty‑seven. The cable, identified in the archive as a United States intelligence assessment, is notable for its technical analysis of the explosion and its…

View the primary source document

Questions about this case

What was National Security Agency Record Concerning The Chinese Hydrogen Bomb Test about?: This is a declassified National Security Agency record concerning the Chinese hydrogen bomb test, dated June twenty‑seventh, nineteen sixty‑seven. S. policy. The document was released to the public through The Black Vault.
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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National Security Agency Record Concerning The Chinese Hydrogen Bomb Test

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