Long worshipped by Tibetans, clay tshatshas have filled the interior of stupas and the statues of Buddhas since the middle of the 11th century.

They are found almost everywhere - in special shrines called Tsha-khang, or on top of Mani stones flanked by prayer flags along tracks, and on the revered snow-peaks or in sacred caves. And Tibetans also carry them in a small amulet boxes to guard against evil.

A transliteration of a Sanskrit word, tshatsha translates as "copy" in English.

Tibetan monks acknowledge them as symbols of Buddhist merit. They are also used as objects to ward of illness and bring good luck.

At least, that is what is widely believed.

But for collectors and researchers, tshatshas are more than religious objects. They are testament to an illustrious history of handicrafts and paper-making techniques exclusive to the Qinghai-Tibet Plateau, as researchers revealed during the annual International Conference on the History of Science and Technology of the Ethnic Minorities, held recently in Beijing.

Small artifacts

Liu Dong, a calligrapher from Tianjin, is an avid tshatsha collector.

Among the several thousand in his possession, the smallest is just 1.5 centimetres in length and the biggest 34 centimetres long.

Some have intricate designs.

One, about 2.5 centimetres in length, resembles a single stupa but actually carries another eight smaller ones inside, each symbolizing a different image of a reincarnated Buddha. Sutra scripts have been engraved on its sides.

"This is an ordinary tshatshas," Liu said.

A more elaborately-made small tshatsha may bear as many as more than 100 stupas.

Tshatshas also feature in varying images of Buddha, whose facial expressions and hand gestures differ from one another. The Buddha, adorned with various symbols and decoration, may also hold different instruments.

Mud, glorious mud

Making a tshatsha has been compared to working with the popular child's play of plasticene. Images are drawn onto a mud mould. After basking in the sun to dry, the moist of mud hardens and a tshatsha is complete.

What marks the difference in designs - the expressions and gestures - is the mould used. "The technique used in making the moulds was considered a most advanced technique more than a millennium ago," Liu said.

It is called the lost wax method.

According to Tang Mingxi, assistant professor from the Hong Kong Polytechnic University, it would cost several thousand HK dollars today to duplicate an ancient mould of tshatsha.

"Yet it would not be as exquisite as an original," Tang said.

The method used today is adopted to make delicate modern sculptures and imitated antiques.

But the moulding technique is not all about tshatsha.

Among Liu's collection, quite a few are relics dating back hundreds of years. But they have retained their bright original colours.

The traditional Tibetan pigment used to colour tshatsha demonstrates the fine knowledge of minerals and paint-making techniques possessed by ancient Tibetans.

"Many people still do not believe that some ancient Tangkha paintings in the Potala Palace were painted 1,000 years ago because they appeared as if they were just finished yesterday," said Ngawang Jigme, professor of the art department of Tibet University in Lhasa, capital of the Tibet Autonomous Region in Southwest China.

The local Tibetan chieftains used to send the paints to the central government as presents.

Artisans made ample use of them while building the Yonghe Lamasery and the White Pagoda during the Qing (1644-1911) Dynasty in Beijing.

Ancient Tibetans developed their own techniques to make mineral paints by hand. This involved pounding and grinding.

The mixing of the different amounts of minerals is a sophisticated procedure.

Nagwang Jigme said people have tried to duplicate the handicraft with a grinding machine, for example, but they have not been able to come up with the same shades as those found in original dyes.

"We once tried to make navy blue - known as Tibetan blue in China - with the help of chemical reagent, but we failed because the reagent also dissolved the little grains of the minerals, which is key to the solid and striking effect of the navy blue," Nagwang Jieme said.

Among Tibetans, there is an old saying concerning paint-making: "strong boy grinds out yellow and white, weak girl green and red."

However, Nagwang Jigme said that the traditional technique is losing its appeal as modern technology has allowed large quantities to be made more efficiently.

Nagwang who started his research on the Tibetan mineral paints in 1998, has found very few Tibetans actually making traditional colour pigments.

Complex colours

Nagwang and his colleagues from the Tibet University have been trying to save and revitalize the traditional techniques.

They search through the mountains and the remote villages across the region and have spent three years learning and recording what they have seen.

"Once, a 90-year-old craftsman told us how to make one type of blue, but when we came back to Lhasa and did exactly what he said, we failed," he recalled.

"Then we had to go to him again and asked him to do it himself. We brought with him all items he might need, including a huge stone mill that weighs many tons," Nagwang said.

"So long as the nature of the pigment does not change, we try to use machines to ease the work load," he added.

"Now workers are using the pigments we produce while repairing the Potala Palace."

Over the years, collector Liu has discovered tshatshas that originated in Tibet are moth-proof.

The secret lies in the paper pulp which was mixed into the mud during their making.

The earliest Tibetan paper, produced about 1,300 years ago, is made from the root of Chinese plant stellera (Radix Stellerae), which contains poisonous ingredients strong enough to keep moth and mice away.

Paper perfection

The Tibetan paper has other merits.

"It has incredible durability so it remains in a good condition for a long time. That's why it serves as the principal writing material for Buddhist scriptures," said Li Xiaocen, professor of Beijing University of Science and Technology.

The paper is also light and flexible.

"It is said it weighs half that of ordinary paper. Although it has not been scientifically proved, it does feel lighter," said Zhang Zhishi, professor of Southwest University for Nationalities located in Chengdu, capital of Southwest China's Sichuan Province, who is in charge of the university museum.

"The technique to make such paper is quite special," Zhang said.

First the crafts people clean the roots and then peel them into three parts - the bark, the inner bark and the soft wooden core.

All three are raw materials but the inner bark, which has special resilience, is the one that makes the special Tibetan paper valuable to Buddhist scriptures.

Workers then tear the inner bark into small pieces by hand and mix some alkali to make the pulp, which serves to whiten the paper.

After several times pulping and heating to refine the mixture, the pulp is ready.

The pulp is placed into the mould and dried in the sunshine, completing the process. The traditional Tibetan paper-making technique flourished as monasteries across the region published numerous Buddhist scriptures.

"It is quite fortunate for us to see the paper and its technique kept alive," Li said.

China Daily