NOT SO LONG AGO a sign hung at the entrance to the Old Monastery of the Stone Buddhas and the Yunkang Caves informing the rare, privileged visitor that "invading imperialist forces, in collusion with the reactionary rulers of Old China, had looted and stolen many of the treasures" of the Caves.

Today only the outline of the sign is visible, but still few see what ranks, along with famous Buddhist caves at Lungmen and Dunhuang, as one of the greatest monuments of Chinese religious art.

Located in the northern cliffs of Wuchow Mountain in Shanxi Province in northern China, some 10 miles west of the industrial city of Datong, is a series of 53 caves stretching for two-thirds of a mile, containing over 51,000 statues - one of the largest stone cave temples in China. Left off most tour itineraries and not readily accessible to Peking, Canton, Shanghai, Hangzhou and other major cities of China, the Yunkang Caves are not often visited by foreigners.

The splendors of the Yunkang Caves are not, however, unknown to the art world. After years of oblivion, the Caves were rediscovered during the first part of the 20th century.Countless visitors came to the shrines to make arrangements for the removal of some of the finer pieces of sculpture. And although (as was alluded to on the sign which formerly hung at the entrance) many of the approximately 1,400 missing statues are now to be seen in European, American or Japanese museums and collections, nothing can compare to actually seeing the magnificent murals, wall carvings and sculptures in their original site.

Our trip to the Yunkang Caves really began last November when the five members of my family applied directly to the Chinese Liaison Office in Washington (which has since become the Chinese Embassy) for visas to visit China. We were uncertain how much independent individual travel was being allowed in the People's Republic, since we had read only about group tours, officially sponsored business trips and some travel by overseas Chinese to visit relatives.

Early in December we were granted 45-day visas, much to our delight. It was then that the planning began in earnest to determine which cities would be on the itinerary to be cleared in Peking by China International Travel Service, the official bureau in charge of travel arrangements for foregin visitors. We made numerous forays through the guidebooks and available literature and finally settled on an ambitious program of places to visit in four weeks, which included Canton, Peking, Datong, Sian, Shanghai, Suzhou, Wuxi and Hangzhou.

On March 25, we entered China via the Kowloon-Shum-Canton train to the accompaniment of martial music and with high expectations of an unforgettable trip. After several days exploring Canton, a long train ride to Peking and a week sampling the wonders of Peking, we began our journey to the Yunkang Caves, one of the key highlights of an already memorable tour.

The train left from the Peking Railway Station at 9:20 a.m. We rode in the "sofe berth" coach, with its velvet-covered seats and lace curtains, reserved for foreigners and important Chinese dignitaries. Although the distance is only 200 miles west of Peking, the trip took eight hours with the train meandering slowly between various sections of the inner and outer Great Walls and making a number of stops.

From the train we could see long stretches of high, arid, almost barren plains winding between the mountain ranges. The dust from the Ordos Desert filled the air so that everthing looked hazy and very dry. All along the route we saw villages which appear to have changed very little over the centuries. In the distance there often appeared cave-like houses carved into hills. The sparsely vegetated land was being intensively worked by using horses to till the soil, but little appeared to be growing.

At length the train pulled into Datong, where we were met by a guide and a minivan from the local branch of the China Travel Service. During the 15-minute ride to the only hotel in Datong where foreigners are housed, we got our first impression of this provincial city of some 800,000 inhabitants. Bicycles with blue or green clad riders abound as do horse-drawn carts loaded with dried corn stalks. Occassionally we saw a truck but rarely a car. The honking of horns, which seems to be a must for driving in China, accompained us all the way to the hotel.

Traditional walled compounds are set off from the main modern boulevard and everywhere chickens scratch in the soil for seeds and insects. Occasionally we could see parts of the old earthen city wall and the roofs of the 10th- and 11th-century Buddhist monasteries. The sky was gray fromthe heavy coal smoke rising over the various industrial works. Datong is primarily known for its production of steam locomotives and coal.

The imposing structure of the hotel is set off from the street by a high wall and was built originally for Russian technicians during the development of Datong as an industrial city. The accommodations are somewhat spartan, with cement floors and very hard beds, but each of our three rooms had a bath.

After an early breakfast, we were met by Miss Wong, our guide, and the same minivan and driver who had met us the previous afternoon at the train station. The narrow, winding road to the Yunkang Caves was heavily traveled by coal trucks, bicycles, horse-drawn carts and carts being pulled by what look like homemade heavy-duty lawnmowers. All along the way there was some evidence of the extensive coal mining works which abound in the Datong area.

Midway to the Caves we passed a dilapidated Chinese temple to Kuan-yin, the goddness of mercy. Nearest to the road was a multicolored the wall depicting three dragons rising out of the waves to fight over several suns. The wall had been added to the temple complex during the beginning of the Ming Dynasty (1368-1644 A.D.). Even in a stae of disrepair it was easy to see that in its heyday the rich blue and gold, three-dragon wall had added a touch of color and splendor to the otherwise more staid temple. Strewn around the crumbling temple buildings and the bell tower were magnificent roof tiles and painted statuettes. The stones carvings in the temple are said to date from the Liao Dynasty (937-1125 A.D.). We were told that restoration was taking place and we can only hope that it will be finished before the temple is forever lost.

At last we drew up to the entrance gate of the long-awaited Caves, guarded through the centuries by two hightly stylized stone lions.The initial view was somewhat misleading with respect to just how extensive the site really is. The entrance is actually part of the buildings of the Old Monastery of the Stone Buddhas, erected during the 17the century. The Old Monastery, with its richly decorated pillars and colorful frescos from the Ching Dynasty (1644-1912 A.D.) depicting guardians and other Buddhist themes, has protected with a series of wooden halls comprised of many bays standing at the mouth of each of several caves. Other monasteries which may have protected the other shrines disappeared centuries ago. Now only caves V, VI and VII of the 20 major caves remain shielded from the elements by the wooden towers.

The building of the cave temples began some 1,500 years ago in the middle of the Northern Wei Dynasty (386-534 A.D.), a non-Chinese dynasty. The first five caves were reportedly started under the supervision of a Buddhist monk during the reign of Ho Ping (460-465 A.D.), when the dynastic capital was located in Datong. Building continued for roughly 40 years with most of the other major caves being completed in the latter part of the 5th century before the Wei Dynasty capital was moved to Loyang.

In the following centuries embellishments were often added to original statues and reliefs. During the dynasties succeeding the Wei, the whole surface of many of the statues and reliefs were clay plastered and plaster has fallen off and all that remains of the plastering is the holes bored into the walls of the caves and on the sides of the statues to hold the plaster to the original carvings.

The number of statues of Buddha is somewhat overwhelming. Ranging in size from a couple of inches to the majestic height of 55 feet, one stands in awe of the nameless craftsmen who created these priceless relics. The walls, arches and ceilings are covered with reliefs on Buddhist themes. Elephants, dragons, phoenixes, tigers, Buddhas, Bodhisatvas, Lohans, devas, flying asparas, dancers, musicians, Vishnu, and Sivas fill the caves. There is a wonderful mix and blending of Indian and Chinese Buddhism. As many as 10,000 little seated Buddhas neatly arranged in rows have been counted in one of the shrines.

Inside caves V, VI and VII, which have been protected by the old monastery from the erosion, we could see how the shrines must have appeared to the hundreds of worshipers who at one time prayed at Yunkagn. Curiously, these were the only caves where we were not allowed to take photographs. We were told that some years ago Japanese photographers had set up elaborate equipment and spent several days filming these three caves with their grand scale and sumptuous sculptures. The result was a beautiful book by Japanese, and since that time there has been a policy of no photographs.

For the 30 or so local sightseers we were as much an object of interest as the caves themselves. This, as it turned out, was not ususual. Not only in Datong but almost everywhere we went in China we drew crowds, whether we went to a local department store, visited a historical site or changed money in a bank.

Three-quarters of the way through the tour of the caves we were served tea in one of the outer buildings of the monastery, a pleasant break. The caretaker gave us a carefully prepared briefing on the history of the site in the local dialect, which in turn was translated by Wong, and answered our many questions about the shrines. Throughout our stay in China we were served tea and given a prepared talk anytime we arranged to see a museum or a factory or a historical site.

Evidence of erosion is everywhere. Most of the caves ar e badly weathered, some in part and some almost in totality. Repairs are underway, and we were informed that when the late French President George Pompidou visited the Yunkang Caves considerable restoration was undertaken. In 1961, the Yunkang Caves were listed by the State Council among the national ancient monuments selected for special preservation. Wong indicated that the Chinese government is spending two million yuan (approximately $1.3 million) to restore and preserve the Caves.

We also heard of the turmoil brought on by the Cultural Revolution. Even in as remote an area as Datong various Red Guard factions arose. Fortunately, one of the factions had a high regard for the past, so the treasures of Datong and Yunkang were protected throughout the Cultural Revolution from destruction by other factions who had no use for the reminders of what they termed the decadent and exploitive past.

The magnificent faded splendor of Yunkang is well worth the extra effort and precious time spent in getting there.I, for one, am glad that the sign at the entrance to the Caves is gone and its absence is perhaps symbolic of the reason we were permitted to take this wonderful excursion into the ancient past. CAPTION: Picture 1, A modern Chinese Buddha, erected since 1949, located in the central hall of the Ling Yin si Temple in Hangzhou; photo by Diana M. Daniels for The Washington Post. The most famous of the Yunkang statues, 35 feet high; by Diana M. Daniels.