IN the arcane art of China-watching, it was quite like old times. Chinese Prime Minister Li Peng regained visibility after a seven-week disappearance, thereby further enhancing the mystery over the reason for his invisibility since his last public appearance on April 24. It was quite like old times because disappearances by Chinese leaders are part and parcel of the politics of the Middle Kingdom. But as the oldest, most powerful Chinese leaders - Deng Xiaoping, Chen Yun, and Peng Zhen - are all in or near their 90s, no one expects them to make public appearances, and they seldom do. Speculation now only arises if Mr Deng fails to be briefly sighted for a year or so. Mr Chen and Mr Peng may be invisible for even longer. It is a sad and sorry comment on the decrepit nature of Chinese politics that Mr Deng remains the most powerful man in China, notwithstanding his personal remoteness - and, very likely, his remoteness from reality too. Back in the last few years of Mao Zedong's era, it was very much as it has been recently with Mr Li. Mao would disappear from view to a greater extent than usual, only to emerge to meet some foreign statesman. Placed in the invidious position of either having to confirm Mao's true state of increasing incoherence, or of telling white lies, the foreigners invariably opted for the latter. So it was only after Mao finally died that the world grasped the extent to which, during his declining years, he had allowed power to slip into the hands of the Gang of Four, led by his wife Jiang Qing. Chinese leaders are never in the public eye to the same extent as politicians in nearly every other country of the world. Just like their dynastic predecessors, the top Chinese communists still live in the Zhongnanhai leadership compound, impenetrable toforeigners and Chinese. Their public engagements are few and far between, and are often reported after they have happened. How Chinese leaders actually spend their time is unknown, except on the rare occasions when they leave the Middle Kingdom for foreign parts. It is assumed by outsiders, that within Zhongnanhai the leaders are aware that communism is being either gradually or rapidly brushed aside by capitalism in the south, along the Chinese coast and in many other parts of China too - but no one can be absolutely sure. Making themselves available for questioning by curious reporters, or subjecting themselves to penetrating interviews - these are political techniques whose time has yet to arrive in the Middle Kingdom. And so to the Prime Minister. Mr Li was last heard of reportedly publicly playing tennis with Singapore Prime Minister Goh Chok Tong on April 24. On April 26 it was announced that Mr Li had a cold, and would not be seeing Philippine President Fidel Ramos. As the length of Mr Li's subsequent absence was extended, so the seriousness of his rumoured illness increased. It progressed to either liver cancer, a heart attack, a stroke or a combination of all three. As his absence was further extended, the political consequences of these dire developments became the additional subject of speculation. So Mr Li was first losing power to party Secretary-General Jiang Zemin, then to Executive Vice-Premier Zhu Rongji, then losing out to both. Neither Mr Jiang nor Mr Zhu came forward to deny this. They presumably knew what was going on, and naturally never thought of ending the doubts of those kept in ignorance. It was left to the television cameras and the arrival of Malaysian Prime Minister Datuk Seri Dr Mahathir Mohamad yesterday to end some of the uncertainty. As the Government could never do any better than ''a cold'' throughout the seven-week disappearance, rumours and doubts about Mr Li's political standing are certain to continue to proliferate. One China-watcher said it all early on in the crisis when he asserted, referring indirectly to the way in which the Chinese currently identify their style of communism: ''It is true that Mr Li has a serious illness - it is a cold with Chinese characteristics.''