China detonated its most powerful nuclear device in an atmospheric test. An H-6 bomber dropped it over Lop Nur desert test site in the remote Xinjiang province of Western China. It was their 21st test, equivalent to 4 megatons of TNT, reportedly 320 times greater than the Hiroshima bomb. A weak radiation cloud drifted high above the U.S. north-west Pacific coast three days later. The monster blast was to demonstrate military strength to both America and Russia. It remains their most powerful to date (2011). A photo released Jul 1977 showed many observers, mostly soldiers, watching the distant blast. A sign in front of them read "Welcome with cheers the inauguration of Hua Kuo-feng as leader of the Party and Liberation Army," who took over from Mao Tse-tung in Oct 1976.

From Moscow, Leonid I. Brezhnev said the Soviets had tested their own neutron bomb. A neutron bomb is designed primarily as a battlefield weapon to use massive bursts of radiation to kill people, rather than explosive force, to minimize damage to structures. Brezhnev gave a 50-minute monologue at the Kremlin to a visting group of U.S. seanators, including astronaut senator John Glenn. Brezhnev stated that "Many years ago our tester [Korlokov] ... tested that bomb. We tested, but we never started production of that weapon." He added, "We do not want to unlease a nuclear war because we are not crazy." He agreed with President Carter that tension had lessened between the two superpowers. The Associated Press reported the quotes based on a shorthand transcript made by a senate aide.