Not so long ago, in a damp little town in central China, I passed an evening - for want of anything better to do - in a karaoke bar.

I had spent a cold day wandering around muddy villages, talking to peasant farmers.

Now, back in the warm and wrapped around a beer, I could just sit and watch people from a dark corner table.

The bar was gaudy and smoky but quite decorous, as these places go.

Its patrons - local officials mostly - favoured ballroom dancing. And those who chose to take the microphone plumped for patriotic songs.

Misty eyes

Sentimental image

As they sang, an enormous video screen above them flickered with sentimental images of China - the Great Wall at dawn, the mountains of Guizhou rising still and precipitous out of the mist.

Towards the end of the evening a paunchy middle-aged man stepped up to the microphone and launched into the well-known number 'Oh, oh, the Paracel islands'. He was good, and the dancers flocked onto the floor.

The Paracel islands are tiny scraps of rock in the South China Sea. No one lives there. China claims them as its own territory, but ownership is disputed. Vietnam and Taiwan claim them too.

Our singer took us misty-eyed through China's emotional attachment to these distant, paltry atolls. "Oh, oh, the Paracel islands", he sang, "return forever to the bosom of the motherland".

On the video screen behind him the Chinese pastoral disappeared, and the Chinese navy loomed, destroyers on exercise in line astern. Square jawed sailors hurtled to battle stations. Guns spat flame across an open sea, aircraft wheeled and dived.

The dancers quickstepped across the floor as on the screen behind them the usurpers of Chinese territory were smashed to pulp.

Territorial disputes

Chairman Mao defeated Chiang Kai-shek

China takes its territorial disputes awfully seriously. They are part of the culture here, the stuff of songs and slogans. They are a reason for pride, passion and unity. China has disputes over territory with almost all of its neighbours.

But the big dispute - the one that really matters, the one that is most likely to see the Chinese navy fighting for real - is over Taiwan.

Fifty years ago the defeated soldiers of Chiang Kai-shek fled before the advancing troops of Chairman Mao until they reached the sea. Then they boarded ships and ran for Taiwan.

Since then, China has been divided, like Germany used to be. But instead of a wall between the rival regimes, there is 90 miles of sea.

Over the years, Taiwan has functioned to all intents and purposes as an independent country. It has become an economic power and a democracy. But it has never called itself an independent country.

Threat of force

Gunboat diplomacy: Taiwan is the big dispute

China watches Taiwan with a jaundiced eye. Beijing wants the island back. The Communist Party says that if Taiwan ever makes a formal declaration of independence, China will attack.

This threat of force has become a kind of evil mantra in Asia. It unsettles the whole region, and makes everybody suspicious of China. It upsets the United States. China does not seem to care.

This week I attended the annual press conference here in Beijing given by China's Prime Minister, Zhu Rongji.

Mr Zhu is a very, very tough, and a very pragmatic, man. His main job is to reform China's economy, to free it from communism, and introduce market forces. It's a formidable task. To do it he needs foreign expertise, investment and trade. He does not need war.

Mr Zhu sat on a dais amid a profusion of flowers. The Chinese state media lobbed a few soft questions, and he spoke mildly about economic policy.

Then someone asked about Taiwan. A thunderous expression came over the prime minister's face. For the next 20 minutes he stormed about Taiwan.

Emotional performance

Zhu Rongji: China would spill blood for Taiwan

He said that if Taiwanese voters chose to elect the pro-independence candidate this weekend, they would never get another chance. He said anyone who thought China would not fight for Taiwan did not understand Chinese history. The Chinese people would spill their blood for Taiwan.

It was an emotional, pugnacious performance. It made headlines around the world, moved markets and sent governments including the US into fits of hand wringing.

But I find it very hard to believe that Zhu Rongji wants to attack Taiwan, or even wants to talk about attacking Taiwan. It would mean the end of everything he has worked for. China would become an international pariah, and would sink back into poverty.

But even Zhu Rongji - China's hard man - is helpless in the currents of nationalism that are coursing through this country.

Such is the emotive power of the Taiwan issue, no one in the leadership can afford to look soft on it. So China chooses to look like a clumsy ridiculous bully, even as it desperately needs friends.

Self-absorption

There is another music video that crops up on Chinese television from time to time. It is a patriotic ballad.

A woman stands on the prow of an elegant wooden boat as it slips down one of China's beautiful rivers. She's got up to look like Guan Yin, the goddess of mercy in Chinese Buddhism - swathed in white silk, long sleeves billowing behind her in the wind.

She is supposed to be an embodiment of the Chinese nation. But in fact she is just self-absorbed and sentimental, helpless on a river of emotion, utterly unaware how preposterous she looks.