Initial stage: Xia (2100-1600 BC)
Around the 21st century BC, China entered the Bronze Age. Archaeologists have found the earliest bronze-making workshops in Erlitou, in the western part of Central China's Henan Province. The site, dating back to the late Xia Dynasty, yielded bronze containers, musical instruments, weapons, tools and personal ornaments, as well as the ruins of a foundry.
Ritual bronzeware from this period was thin-walled and cast by a clay piece-mould technique that was already developed. Its forms began to show decided characteristics. The animal-mask motif appeared at this stage, as did the use of turquoise inlay.
Early and middle Shang (1600-1300 BC)
During the early and middle Shang Dynasty, bronze casting evolved further.
Rituals that mainly involved drinking vessels became important. Bronze weapons increased in variety.
The animal-mask motif decorated many bronze pieces, executed with bold, deeply-cut linear elements. Their decoration became even more complex. The mould-making process became sophisticated, and an ingenious technique was developed for casting a complicated shape in a sequence of separate pours of metal. Much of the bronze dating from this time has been unearthed along the middle reaches of the Yellow and Yangtze Rivers.
Late Shang -- early Western Zhou (1300-1046 BC)
The late Shang and early Western Zhou dynasties witnessed the zenith of Chinese bronze casting. During this period the bronze used in rituals (originally drinking vessels), changed.
Although at first the early Western Zhou people followed the Shang ritual system, they gradually developed ceremonies in which food containers played an important role. Using techniques that produced both high and low reliefs, artisans designed bronze entirely covered with elegant patterns.
They also further refined the mysterious animal-mask motif.
Inscriptions first appeared on late Shang bronze. These inscriptions on Western Zhou bronze are often lengthy.
Middle Western Zhou -- early Spring and Autumn (11th -- early 7th centuries BC)
During the middle and late Western Zhou Dynasty, food vessels increasingly dominated ritual ceremonies.
Regulations specified the numbers of ding tripods, bells, and other bronze appropriated for the King's use and for the use of lower-ranking nobles.
New bronze shapes were developed in flowing curvilinear lines or with single straight strokes. Bronze inscriptions increased in importance and especially long inscriptions were cast on some major vessels.
In the early Spring and Autumn Period, bronze shapes and motifs continued the traditions of the middle and late Western Zhou period.
Each feudal stage maintained its own bronze-casting industry. Though some bronze pieces were roughly cast, the vessels produced in the foundries of later stages were sometimes very fine.
The stage of renewal:
Middle Spring and Autumn -- Warring States (late 7th century -- 221 BC)
The Chinese bronze tradition enjoyed a second flowering, beginning in the middle Spring and Autumn Period.
As the bronze industries in the feudal stages matured, regional styles with unique characteristics arose.
Bronze cast in the northern states of Jin and Qin, the eastern states of Qi and Lu, and the southern state of Chu reflected a mutual beneficial exchange of ideas and materials and their bronze arts achieved great splendor.
While the ritual functions of the bronze vessels gradually diminished, their use as daily utensils increased, with the result that new and delicate vessel types appeared.
Decorative dragon patterns became minute and intricate and scenes of daily life were used for the first time as bronze decoration.
The lost-wax techniques and the use of impressed moulds enabled artisans to obtain rich inlay decorations of unsurpassed delicacy and intricacy.
(China Daily November 2, 2004)