AS ONE proceeds south along the thousand kilometre long Hexi Corridor of Gansu, it soon becomes obvious that this all-important artery of trade between east and west was also a battleground for dominance between the nomads of north-central Asia and the civilisation of the central plains of China.

Military garrisons and trading outposts like Dunhuang were so crucial to the survival of the Han Empire that they were protected by passes that marked the extremities of the Great Wall. Two key passes in the Gobi guarded the entrance to the Han realm - Yumenguan to the northwest of Dunhuang, and Yangguan to the southwest. Both were immortalised by Tang dynasty poets, one of whom wrote, "The spring wind never comes to Yumen Pass" - an apt description of the danger and desolation beyond the Wall.

I was told these ancient fortresses lay in ruins so, from Dunhuang, we headed 400km south to Jiayuguan which guards the westernmost end of the Ming dynasty Great Wall.

The expressway from Dunhuang to Jiayuguan passed through a variety of desert landscapes at altitudes above 1,000m. We crossed sandy terrain that was flat and completely featureless; stony stretches, scrubland and barren mountains. All were equally bleak and it is undoubtedly an uphill battle for the farmers trying to eke out a living in the impoverished countryside.

Dubbed "The Grandest Pass under Heaven", Jiayuguan is fully restored and sits on a ridge in the high desert. It is said that anyone leaving or entering the Middle Kingdom by this route during the Ming dynasty would have had to pass through the massive gates beneath Jiayuguan's 17m-tall eastern and western watchtowers, both of which sit on top of 10m-high walls.

Within Jiayuguan's gates is a massive courtyard designed for military drills. And typical of Chinese fortresses, there is an inner city and an outer city with a specially designed "killing zone" in between; enemies who managed to penetrate the outer wall would have had virtually no chance of escaping this enclosed area.

I climbed to the top of the fortress walls and looked out over the harsh landscape of the Gobi. On one side was an oasis settlement and, on the other, a marvellous view of the ruins of an un-restored original wall. Although the desert looked no different on either side of the old wall, our guide said in ancient times it was the psychological divide between the wilderness to the west and the Han world to the east.

Jiayuguan was so meticulously planned and so carefully constructed, and its architect said to be such a gifted designer that he was able to calculate the exact number of bricks needed to complete the fort. However, workers found one extra brick when putting the finishing touches on the structure, and they attached it above a gate as testament to the architect's genius.

Romance and chivalry

Barely 20 minutes from Jiayuguan is the city of Jiuquan, a Han dynasty garrison whose name I have always associated with romance and chivalry. For it was here 2,100 years ago that Han Emperor Wudi rewarded his brilliant young general Huo Qubing with imperial wine in honour of his triumph over the Xiongnu (Huns). Although Qubing was barely out of his teens at the time, he had wrested the territory from the encroaching Xiongnu who threatened Wudi's realm. Qubing chose to share the wine with his victorious troops and poured it into a spring from which all could have a sip; hence the name Jiuquan (Wine Spring).

To this day, the Wine Spring remains crystal clear. A park has been built around it with bronze sculptures of halberd-wielding Han dynasty soldiers ready to do battle. A pavilion sits in a large lake surrounded by willows and poplars, most of which were still bare. In the cold of that early spring morning the lake had a dreamy, melancholic ambience.

No wonder then that Jiuquan has been the inspiration of many a poet, including the Tang dynasty's frequently inebriated Libai whose ode to Jiuquan is immortalised in stone at the park: "If Heaven did not love wine, the Wine star would not be in the sky. If the Earth did not love wine, there would be no Wine Spring (Jiuquan)".

The Han fondness for drink encouraged an appreciation of wine cups and related implements and Jiuquan is well-known for the phosphorescent yeguang bei - "luminous" cups made of a jade-like, dark greenish stone from the nearby Qilian Mountains. A salesperson at a yeguang bei factory said that when filled with wine, the cups appear luminous under moonlight.

Compared to the hard-edged fortress town of Jiayuguan, Jiuquan seemed to have a gentle, mildly quixotic atmosphere. Hardly surprising, when so much of its history revolves around brave soldiers and gallant young generals, and the wine and moonlit cups celebrated in odes and poems.

Ziying is currently exploring another rural school project in China. The country's rich culture and history are her lifetime passion. She can be contacted at ziyingster@gmail.com.