As time flows on, these forts - which were once used to station troops, defend against bandits, and safeguard villagers - are crumbling into ruins.

Zhangbi, one of these centuries-old forts, surpasses all others with its unique historic, cultural, religious, military and architectural significance.

Zhangbi, now a village in Longfeng County, sits on hilly land some 10 kilometers southeast of Jiexiu.

Surrounded by gorges on three sides leaving only a southern link with the outside, Zhangbi appears like an isolated island when viewed from afar.

The unique fort is laid out like a complete city, including imposing defenses, a water supply system, a political and cultural center and a religious arena, all of which distinguish Zhangbi from conventional forts and make it more like a small village.

More than 1,300 years have passed and the fort still functions well due to the villagers' preservation efforts. Life has changed little for the villagers over the centuries with their ancient buildings and traditional way of living.

"Rules handed down from our ancestors keep Zhangbi alive today," said Yang Chengrui, the village head. "All houses must be at least 20 meters away from the fort wall," he said. At the foot of the wall still stands a stone tablet saying, "chopping only, no excavation," referring to trees planted along the fort wall for the purpose of wall protection. The village rules also prohibit spreading dung and dirt along the wall.

Covering an area of 120,000 square meters, about three times as large as Tian'anmen Square in Beijing, Zhangbi is criss-crossed by an S-shaped main road and several small lanes stretching to each corner.

"Such a layout is intended to maintain fengshui for the castle," said Zheng Guanggen, a local archaeologist. The principles of fengshui, which refers to good geomantic omens, are often applied in Chinese construction.

There are only two gates in the fort: one in the north and another in the south. The North Gate built with bricks faces the piercing gorge, and is seldom in service due to inconvenient transportation. Meanwhile, the South Gate and southern part of the fort are quite important. According to Zheng, they are believed to represent a dragon.

The fort moves lower south to north. Built with stones, the South Gate has a stone-carved dragonhead on top. Outside the gate, there are nine red-stone roads, resembling dragon palps.

The S-shaped main street is paved with slabs. The street is three or four metres wide and 300 metres long, resembling a dragon's body. Along the dragon body, three columns of parallel red slates were laid, from the South Gate extending to the north, resembling the dragon's backbone.

Along the main road stretching from south to north, seven small lanes - three on the east and four on the west - constitute a T-shaped layout.

The buildings along the four lanes on the west are exquisitely elegant because they were the dwellings of the rich in the old times. Most of them remain unspoiled.

Along the main street, simple-looking shops and houses are well laid-out. "Zhangbi was a business hub once in history," said Zheng, adding that all these shops and houses were used as stores at that time.

Who Built the Fort and Why did They Make it so Imposing?

Legends say that Zhangbi was probably built by Liu Wuzhou, a general in the late Sui Dynasty (AD 581-618) and early Tang Dynasty (AD 618-907), when the general had a conflict with Tang Emperor Li Shimin near Jiexiu.

Taking advantage of the easily defended terrain, Liu dreamed of being an emperor himself. But he was eventually defeated.

However, because of the good relationship between Liu's troops and the local people, after the downfall of the Tang Dynasty the villagers constructed the Kehan Memorial Temple, inside which are statues of Liu Wuzhou and his two subordinates Song Jingang and Yuchi Gong. The temple is still intact today in the village.

Zhangbi was reinforced during the Ming (1368-1644) and Qing (1644-1911) dynasties when Shanxi experienced a booming economy. Many people in Zhangbi went to do business in nearby Jiexiu and got rich. And they brought their wealth back home.

At that time there were four rich families in the village - the Zhangs, the Wangs, the Jias and the Jins. To better preserve their possessions, they chose to build a castle.

Military Function

But what distinguishes Zhangbi the most is its military significance, increased by a solid wall and an underground tunnel.

"The whole tunnel is 5 kilometres long in an S-shape with three layers," Zheng said.

The top layer is 1 to 2 metres deep; the middle part is 8 to 10 metres, and the bottom is 17 to 20 metres below the surface. Only one person can pass at a time.

"The construction of Zhangbi's tunnel reflects ancient crafty architectural ideas," said Zheng, who couldn't help expressing his admiration.

"Not only does the tunnel have defensive facilities such as large-scale holes for stationary troops, it also has granaries and stables. It also features attacking devices including traps, shooting posts, communication channels, lookout posts, as well as drainage and emergency exits," Zheng said.

"All six tactics - advance, retreat, attack, defence, hide and escape - are involved in the design of Zhangbi's underground tunnel."

The tunnel is connected to 10 wells in the fort, which offers better ventilation. Caves were built at intervals in the tunnel and were used to fight against invaders. The small ones can hide two or three people while the largest holds as many as 20.

On the bottom layer there were several rooms for grain storage. Each was able to house 8 to 10 cubic metres. On both the top and the bottom of the caves there were holes or passages, either used for ventilation or for loading grain.

"From the passages at the bottom our ancestors transferred grain to the valley in the west," Zheng said.

In addition to several small shafts in the walls, the commanding caves were also installed with lookout posts.

The unique military construction device of an "obvious fort and hidden tunnel," which is rare in China, together with its wealth of historic and cultural relics distinguish Zhangbi as an unequalled cultural treasure.

Zhangbi is a magical ancient architectural compound abounding with religious stories, military legends and cultural heritage.

The fort is believed to be one of the relics of both military and household use in the country, not only representative of village construction in China's small-town planning system, but also of ancient military architecture, according to experts from the Ministry of Construction and the Military Science Academy of the Chinese People's Liberation Army.

However, due to insufficient materials, the history of the construction of Zhangbi is not substantiated yet. Many elements still remain mysterious.

(China Daily August 19, 2002)