THIS time the cannons which China has announced it will fire in the Taiwan Straits loaded, and the question puzzling everyone is why?

Mao Zedong once famously told Richard Nixon not to worry about Beijing's fiery propaganda it was nothing but the sound of "empty cannons". As for Taiwan rejoining the mainland, the Chairman added with dialectical assurance: "Let it come after 100 years." Now that the military manoeuvres will use live ammunition the timetable has speeded up alarmingly.

Hong Kong, whose own jitters are compounded by the Taiwan Straits crisis, is partly responsible. President Jiang Zemin has made it clear that with Hong Kong (and Macao two years later) about to return to the motherland, Taiwan is next on a now urgent agenda.

China is alarmed by the firming up of Taiwan's de facto independence as next week's presidential elections complete the formal transition to democracy. But Beijing's impatience seems to be driven by some deeper source.

This week a Hong Kong newspaper claimed that the veteran leader, Deng Xiaoping, had personally authorised a hardening of policy towards Taiwan in order to "guarantee" its reunification.

Mr Deng, 91 last August, said some time ago that he was determined to stay alive until Hong Kong is handed over next year. Could he possibly now be hanging on for the biggest prize of all? Or could ambitious Beijing leaders be exploiting the crisis on the pretext that Mr Deng has got tired of waiting?

A desire to complete the recovery of China's lost territories is not just an elite concern, and patriotism has become increasingly a substitute for previous ideals, like socialism. Especially since the Beijing massacre, Mr Jiang and other leaders have sought to boost national morale by some simple historical lessons.

China has a "glorious history" of 5,000 years and is one of the world's great countries. Hong Kong was seized by the British and Taiwan illegally occupied, with US connivance, by Chiang Kaishek's Nationalists in 1949 after the victory of Mao's revolution.

On swaying buses and trains deep in the inland Chinese provinces, complete strangers will deliver these received truths with complete conviction. But in the indiscreet atmosphere which anonymous travel encourages, quite a few also offer a more hard headed analysis of the present power game in Beijing.

"When there is confusion at the centre", runs this man or woman on the slow train to Chongqing argument, "the army steps in and demands action."

The "confusion", they argue, arises from the political paralysis caused by what may well be Mr Deng's medical paralysis. Chinese officials say, with deadening repetition, that he is as well as can be expected for someone of his age. But how well?

There were strong indications last summer that top generals in the People's Liberation Army (PLA) had put on pressure to ratchet up Beijing's reaction to the provocative (though unofficial) visit of Taiwan's President Lee to the US. Then as now, Beijing said it with missiles in the East China Sea.

The PLA would probably welcome the chance to show some military muscle over Taiwan the island has been a source of intense frustration for nearly 50 years. Plans to complete its "liberation" by launching an invasion force in 1950 were, thwarted by the outbreak of the Korean War.

The US, which had seemed to back away from its unsuccessful Chinese Nationalist clients, then reversed course, interposing the Seventh Fleet in the Taiwan Straits.

In 1955 and again in 1958 China stepped up pressure by bombarding the "offshore islands" occupied by the Nationalists but close to the mainland.

Although these two crises were labelled in the West as a threat to peace, they were never a prelude to invasion. Each was used by Beijing to send a message, first to the US and then to the Soviet Union, that China should not be ignored in their superpower summitry. They were early examples of "empty cannons".

After the Nixon visit in 1972 opened the way to "normalising" US China relations, the threat of war over Taiwan receded to apparent vanishing point. While Taiwanese flocked to invest in the motherland, many mainland officials professed open admiration for the island's superior economic performance.

By the end of the 1980s, Taiwan had become a muted issue in USChina relations. As cultural and economic ties expanded across the Straits, Washington could continue to supply military technology to the island, and to mask its relations through links such as the non official "American Institute" in Taiwan.

ASIA WIDE opinion was lulled more generally by the new comforting myths of the post Cold War era.

At international conferences in Tokyo, Seoul and Singapore, delegates from China, Japan, the US - and even Taiwan, masquerading as "Taipei (China)", could all agree the age of geo political contention was dead.

Instead, all would share the common goals of the new geo economic age. Issues of sovereignty could be shelved in mutual efforts to achieve the new East Asian Economic Miracle.

This always naive view reached its peak with speculation about the post Deng emergence of a Greater Southern China embracing harmoniously in economic symbiosis Hong Kong, Taiwan, and the booming south Chinese coast.

But the conditions for a new conflict have been building up on both sides of the Straits as political life moves in opposite directions. In China it has become aged and more authoritarian, less capable of the flexible thinking that had begun before the Beijing massacre. In Taiwan it has become younger and more democratic, compelling President Lee and the Nationalists to shade their commitment - shared previously with Beijing - to "one China".

However much Beijing has overreacted, it was Mr Lee who disturbed the status quo by supporting the idea of dual Taiwan/Beijing representation in the UN, and paying a high profile "private" visit last year to his PhD alma mater of Cornell University. In doing so he weakened the personal authority of President Jiang in Beijing, who had put forward an "eight point" policy on Taiwan which was widely seen as more conciliatory.

Four years ago Mr Lee denounced opposition leaders who called for Taiwanese independence as "pariahs who will cut themselves off from our history and culture". Now he presents his party as following a "middle path" between independence and reunification with Beijing.

Even more alarming for Beijing, he is also obliged to admit that a post election rapprochement might be possible with the pro independence Democratic Progressive Party.

"There is only one China," Richard Nixon is reputed to have mused trickily on his return from Beijing where he had signed a communique acknowledging the fact. "But we did not say which one!"

The problem has subtly changed now it is that there is only one Taiwan - whatever it may be called. Under whatever name, and in spite of economic miracles, the old issues left over from history refuse to go away.