THE dragon's eye of any tour of China must surely be a boat ride through the Yangtze Gorges - in fall, when the water is high enough for a side trip by sampan through the even more spectacular ``little'' gorges of the Daning tributary. The``dragon's eye,'' of course, is the final touch that turns a good Chinese painting into a masterpiece. Tourists are well advised to take this trip as soon as possible. A hydroelectric dam that was commissioned in 1981 has already raised the water in the upper Yangtze about 70 feet; the next stage of the project will raise the level another 60 meters by the end of the 1980s; and further power development is in store for this 3,800-mile river.
The ride upstream starts at Wuhan; the ride downstream at Chungking, the somewhat raw river town that is now the largest city in China. Tourists may sail either by regular Chinese passenger boat or by special tourist liner, and last year tickets could generally be bought on the spot if travelers had a few days' leeway in their schedules. This is often the only way for individuals to arrange the trip, since the tourist organization in China, as yet noncomputerized, is frequently unable to confirm advance reservations.
For those Westerners not on a student budget, the liner at several hundred dollars is probably preferable. Whatever the disadvantage of insulation from Chinese life, the cruise ship does anchor overnight to ensure that passengers go through the gorges in daylight, while the scheduled passenger ship plows on night and day. All double rooms on the cruise ship have an outside view as well as shower and toilet facilities; all meals are included in the price.
The ride on the first day out of Chungking - often through fog - introduces the passenger to the rhythm of the upper reaches of China's longest river. There is surprisingly little boat traffic on what used to be a main thoroughfare, and there are few settlements.
The most common signs of life are scattered stonecutters in vivid pink or green or blue undershirts, chipping at rocks by hand as their ancestors did for centuries. Sometimes there is a quicklime plant pouring white pollution into the river; occasionally there is timber being floated downstream. The steep surrounding hills are naturally terraced, crested with single-file rows of tufted Chinese pines.
At Shibao Zhai the first signs of history appear, with the 19th-century, 11-story pavilion in pagoda form reminding passers-by of the Three Kingdoms period in the third century BC and of the numerous battles fought by these kingdoms on the Yangtze.
Further on comes Wanxian, the grand destination of the ill-starred junk in ``A Single Pebble,'' John Hersey's evocative novel about the trackers who hauled boats up the treacherous Yangtze by sheer muscle power as late as the 1930s.
It is no longer the teeming port that Hersey describes, with junk crews raucously celebrating their victory over the upstream rapids and shoals and with more elegant passengers luxuriating in their first hot baths in weeks in mandarin-run inns. But the cruise liners that stop here overnight provide enough trade for shopkeepers and rows of private street vendors to stay open late. Long after dark tourists can sample the local pomelos and buy painted stones or wicker chairs or a myriad of other products.
Early the second day passengers enter Qutang Gorge, the Yangtze's first and most dramatic. For five miles, towering cliffs on both sides funnel the Yangtze into a turbulent 350- to 500-foot wide raceway flowing at a speed that rivals even the Colorado River in the US. In recent decades the Chinese have blasted out dangerous rocks and shoals and installed navigation lights, and the cruise ship rides the present course smoothly.
A retired American sea captain and shipbuilder in our group of passengers confirms that it's still tricky to navigate. However, since the water level can vary by as much as 170 feet, the force of the current easily shifts riverbed boulders and silts up old channels, and any loss of control over engines and rudder could quickly sweep the ship sideways. The visitor can only endorse Li Bai's (Li Po's) poem complaining that ``Travel to Sichuan [the province of the upper gorge] is as difficult as climbing up to the sky.''
On the right side of the gorge, square pegholes scaling the cliff mark the place where a retainer of Meng Liang in the Sung Dynasty sought vainly to retrieve the body of his murdered general from the high cave it had been buried in. Coffins from such burials have been discovered in this area, though none remains today, so far as is known. (In the alternative and more romantic explanation of the pegholes, the wooden steps extending out from them once enabled Meng Liang's trapped army to scale the cliff and surprise the enemy army commanding the heights.)
Before noon, the cruise ship docks at Wushan, and passengers transfer to sampans to penetrate the ``small'' Daning gorges. On the little boats the front seat is best, not only to test the rapids by fingertip and to photograph the panorama of mountains that shoot straight up hundreds of feet, but also to see just how the boatmen pole the sampans' weight over the shallows and to hear their accompanying chants. This is the closest a tourist can come today to experiencing that intuitive understanding of the Yangtze's moods displayed by Hersey's trackers.
Along the Daning River, pegholes on the sheer cliffs form a long horizontal, rather than diagonal, pattern and mark the normal walkways used for centuries both by trackers and the valley population. Periodically, the gorges flatten out to show fields worked by water buffalo and crops planted in erosion-prone vertical strips.
The small gorges, with their monkeys, wild goats, and sometimes mandarin ducks, have been open to foreign tourists only since 1985. In September 1986 our group was the first of the season to make the side trip, after melting snow in the distant mountains replenished waters that our cruise captain said were the lowest in 40 years.
Back on the Yangtze itself on the third day, the second large gorge - the Wu (27 miles long) - is much gentler than the Quantang, and so is the third - the Xiling (47 miles long). They have their own enchantment, however: Wu's 12 mountains include Goddess Peak, associated with the legend of the taming of the waters. Xiling, once notorious for its whirlpools, rapids and reefs, includes the colorfully named Gorge of the Sword and Book on the Art of War, Gorge of Ox-Liver and Horse-Lung, and Shadow-Play Gorge. It also includes Zigui, hometown of a wise but ignored statesman who committed suicide in 278 BC and has been celebrated in China's annual Dragon Boat Festival ever since.
The downstream tour ends on its fourth and fifth days with excursions to China's largest dam and power station at Yichang, and to the Yueyang Tower, made famous by Tang poets.
For the greatest enjoyment, passengers should do their homework before coming on the voyage. No maps or brochures are distributed on the boat. Information given over the loudspeaker is somewhat erratic. Tour guides tend to be more interested in watching Western movies on the lounge video than in pursuing the answers to questions posed by tourists.
A traveler who comes with the following books and maps is well equipped to get the most out of the trip: Hersey's ``A Single Pebble''; ``Tourist Atlas of China,'' a general guide on sale at the Beijing Friendship Store; and ``Along the Changjiang River,'' published by the China International Travel Service in Wuhan. Also useful is ``The China Guidebook, 1987 Edition,'' by Kaplan, Sobin, and de Keijzer (Eurasia Press/Houghton-Mifflin Co.) It is a comprehensive guide to travel in China, giving names and addresses of contacts for individual, business, or group travel from anywhere in the world.