Early in the morning of Feb. 17, 1979, Chinese artillery batteries and multiple rocket launchers opened fire all along the Vietnamese border with protracted barrages that shook the earth for miles around. Then 85,000 troops surged across the frontier in human-wave attacks like those China had used in Korea nearly three decades before. They were decimated: the well-dug-in Vietnamese cut down the Chinese troops with machine guns, while mines and booby traps did the rest. Horrified by their losses, the Chinese quickly replaced the general in charge of the invasion that was meant, in Beijing's words, to teach Vietnam a lesson, and concentrated their attack on neighboring provincial capitals. Using tanks and artillery, they quickly overran most of the desired towns: by March 5, after fierce house-to-house fighting, they captured the last one, Lang Son, across the border from Pingxiang. Then they began their withdrawal, proclaiming victory over the Cubans of the Orient, as Chinese propaganda had dubbed them. By China's own estimate, some 20,000 soldiers and civilians from both sides died in the 17-day war. Who learned the bigger lesson? The invasion demonstrated a contradiction that has forever bedeviled China's military and political leaders: good strategy, bad tactics. The decision to send what amounted to nearly 250,000 troops into Vietnam had been taken seven months before and was well-telegraphed to those who cared to listen. When Deng Xiaoping went to Washington in January 1979 to cement the normalization of China's relations with the United States, he told President Jimmy Carter in a private meeting what China was about to do--and why. Not only did Beijing feel Vietnam was acting ungratefully after all the assistance it had received during its war against the U.S., but in 1978 Hanoi had begun expelling Vietnamese of Chinese descent. Worst of all--it was cozying up to Moscow. In November 1978 Vietnam signed a treaty of friendship and cooperation with the Soviet Union. A month later the Vietnamese invaded Cambodia, a Chinese ally. Although Hanoi said it was forced to do so to stop Pol Pot's genocide and to put an end to his cross-border attacks against Vietnam, Deng saw it as a calculated move by Moscow to use its allies to encircle China from the south. Soviet adventurism in Southeast Asia had to be stopped, Deng said, and he was calculating (correctly, it turned out) that Moscow would not intervene in a limited border war between China and Vietnam. Carter's National Security Adviser, Zbigniew Brzezinski, said Deng's explanation to Carter of his invasion plans, with its calculated defiance of the Soviets, was the single most impressive demonstration of raw power politics that he had ever seen. At the time Deng was consolidating his position as unchallenged leader of China. Having successfully negotiated normalization of relations with Washington, he wanted to send a strong signal to Moscow against further advances in Asia. He also thought the Carter Administration was being too soft on the Soviets, although he did not say as much to his American hosts. Hanoi, for its part, was unfazed by Deng's demonstration of raw power. The Vietnamese fought the Chinese with local militia, not bothering to send in any of the regular army divisions that were then taken up with the occupation of Cambodia. Indeed, Hanoi showed no sign of withdrawing those troops, despite Chinese demands that they do so: the subsequent guerrilla war in Cambodia would bog down Vietnam's soldiers and bedevil its foreign relations for more than a decade. The towns captured by the Chinese were all just across the border; it is not clear whether China could have pushed much farther south. Having lost so many soldiers in taking the towns, the Chinese methodically blew up every building they could before withdrawing. Journalist Nayan Chanda, who visited the area shortly after the war, saw schools, hospitals, government buildings and houses all reduced to rubble. The war also showed China just how outdated its battlefield tactics and weaponry were, prompting a major internal review of the capabilities of the People's Liberation Army. The thrust for military modernization continues to this day, even as the focus of China's generals has shifted from Vietnam back to Taiwan--a pesky little irritant that could cause Beijing even bigger problems if it decides to administer another lesson.