China Tibetannet  In the Tibetan-inhabited areas, the parapet walls of  important halls in monasteries such as large "Zhacang"  (group unit name of monasteries, the largest one being "Coqen", followed by "Zhacang" and "Kammcun", and the smallest "Micun") and sutra hall, are reddish brown, offering a distinct contrast with the white walls. As its materials are made of shrub branches named "Benma" in Tibetan, which are bundled and then dyed, they are called Benma walls.

Benma wall in the Main Hall of the Tashihungpo Monastery. Photo by Wu Yi

After being peeled off and sun baked, the Benma branches and trunks are chopped into sections 30 centimeters long and, in bundles as thick as an arm, are then piled up to form Benma walls. When building up such walls, a layer of clay stones would be placed on a layer of bundled Benma branches and then tamped down. Then, one after another, the walls would be built up to the top and waterproofed. The reddish brown paint that is used gives the distinctive coloring of the Benma walls.

Benma grass used to make Benma walls. Photo by Cedog
From the view of construction technology, this kind of wall body can reduce the weight of wall, playing a good role in overall weight-reduction of tall Tibetan-style buildings; regarding their appearance, Benma walls play a decorative role by offering a strong color contrast with the dominant white, resulting in a good visual aesthetic feeling. With a reddish brown parapet walls on a white wall body and with the black stripes on the window edges, the wall color changes from being monotone to colorful and from being light to being dignified, which enhances the seriousness of the whole architecture, just the sort of feeling we get from the Potala Palace, Jokhang Monastery and the three major monasteries in Lhasa.
In Tibetan history, reddish brown Benma walls were a special treatment given to for particular buildings, and were not just for anyone. In old Tibet, when the system of combining politics with religion was followed, all the religious buildings like monasteries were distinguished by Benma walls, golden tops, and treasure umbrellas and treasure bottles. In fact, apart from religion, the strict class system that prevailed in Tibet was also reflected in architecture. Thus, the ruling and ruled classes were strictly separated by such symbols as building size, height, decoration and more subtle distinctions such as mounting stones before gates. In size and height, noble houses were distinctively different from the buildings of common people, including being able to have Benma walls. In old-style noble's houses, we can find some with Benma walls, and the most representative being Chongsekang and Nangzeshag on Barkor Street North and Sangzhub Phodrang on Barkor Street South. These constructions are old-style noble's houses occupied by famous noble families of the old regime. Except for them, there are no Benma walls in non-religious Tibetan-style architecture.

Tibetans processing grass for the making of Benma walls. Photo Cedog

In the view of this writer, however, Benma walls originated from the architecture created by the common people. In Tibetan farming areas, it can be found that, on the top of farmers' houses walls there are circles of closed fitted, piled firewood or cow dung cakes, which offer a color contrast to the white walls. Originally, farmers made good use of the spaces on wall tops to pile up firewood in order to save living space as well as to prevent thieves from climbing over the walls. Clever Tibetan architects got inspiration from this scene, and adopted it in the building of wall bodies.
Benma walls occupy an important position in Tibetan-style architecture, but due to rare materials, complex production process and high cost, it is impossible to adopt it on a large scale in modern Tibetan-style architecture. However, as Benma walls are an indispensable part of traditional Tibetan-style architecture, we should investigate how to preserve the distribution of Benma walls, the processing and wall construction crafts and their role. Then this aspect of national architecture can be preserved for ever and will play a role in maintaining ancient Tibetan constructions.