The officers also carried different ranks. So far only one high-ranking officer has been found in Pit 2 and six middle-ranking officers have been mostly discovered in Pit 1.

Though not completely excavated, the newly found officer seems to be of a low rank, according to Xu. "The discovery of the officer will help us in the study of the Qin Dynasty army system," he said.

Two chariots were also discovered with four horses beside each. "It is the first time we've unearthed such an arrangement of chariots in the pit. Those that we found before had a dozen warriors in between," said Cao Wei, Deputy Curator of the Qinshihuang Terracotta Warriors and Horses Museum.

Many weapons including lances, swords and arrows that are still sharp have been discovered.

Visitors and tourists can still visit the terracotta warriors freely during the third excavation. The excavation process can be seen clearly.

Liu Zhancheng, head of the archeology team at the terracotta museum, estimated this excavation would hopefully unearth about 150 terracotta warriors over the next few years.

Many mysteries

The army of terracotta warriors and horses is one of the greatest archeological finds in modern times. Peasants digging a well discovered it in 1974 in Lintong County, 35 km east of Xi'an.

The first formal excavation of the site lasted from 1978 to 1984 and uncovered 1,087 clay figures. A second excavation, in 1985, lasted a year and was cut short for technical reasons.

The ancient relic site includes three pits. The 230-meter-long and 62-meter-wide Pit 1, which is currently being excavated, is believed to hold about 6,000 life-sized figures. More than 1,000 were found in previous excavations, according to museum curator Wu Yongqi.

Holding cavalry and infantry units as well as war chariots, Pit 2 is thought to represent a military guard. Pit 3 is the command post, with high-ranking officers and a war chariot.

Most experts believe Pit 1, the largest of all three, houses an army of archers, infantrymen and charioteers that Emperor Qinshihuang (259-210 B.C.), the first emperor in China for whom the underground army was built, hoped would help him rule in the afterlife.

The State Administration of Cultural Heritage approved a plan to excavate an area of 200 square meters in Pit 1 in 2009, which will likely continue if the dig proves fruitful.

Though there had already been two excavations in Pit 1, they only covered 2,000 square meters in its eastern part. The third excavation in the middle and western parts of the pit will help give a clear picture of the distribution of warriors, their weapons and chariots, said Wu.

There are still many mysteries about the tomb of the emperor, which need to be solved.

History books indicate that the underground palace of the emperor's tomb is much deeper than has been reached to date.

According to what is recorded in the Historical Records, which is said to be the first history book of China and was written 2,000 years ago, the underground palace of the emperor has many astronomical and geographical indicators, which still remain shrouded in mystery.

A well-preserved mummified female body discovered in Mawangdui, on the eastern outskirts of Changsha, central China's Hunan Province, in the 1970s gave the whole world a great shock. As the woman lived around roughly the same time as Emperor Qinshihuang, researchers wonder whether the body of the emperor is preserved as well.

The preservation problem

Richly colored clay figures were unearthed from the mausoleum of Emperor Qinshihuang during the previous two excavations, but once they were exposed to air they began to lose their luster and turn an oxidized gray color.

The museum has been cooperating with a German cultural relic department for years, trying to find a satisfactory way to preserve the color of the terracotta, and has made some headway.