Note that nobody exactly says what it is.

Besides just being a pretty sight for the eyes, Yangzhou lacquerware is also impressively resistant to heat, moisture, and corrosion. Appreciating its beauty hardly tells of the complex process and ancient history behind this special creation that some call the height of ancient Chinese technological artistry. On top of this, lacquerware technology continues to improve, as today its forms have evolved into a diverse display, more varied and intricate than at anytime in its two thousand year history.
During the Warring States Period (475-221 B.C.) the first coats of lacquer paint were laid on in Yangzhou, but practicality rather than aesthetics dominated. By the Western Han dynasty (206 B.C.-A.D.24) though, lacquerware had already become a colorfully decorated, developed art form. Lacquerware became such a cherished product that it became predominantly a gift of tribute. Apparently during the Tang dynasty in just one trip to the capital Chang'an (Xi'an) a load of 10,000 lacquerware pieces were delivered. By the Ming and Qing dynasties Yangzhou lacquerware had reached the most experimental proportions when forms involving jade and mother-of-pearl inlays were born. The celebrated "Eight Eccentrics" of Yangzhou also had their calligraphy and paintings etched into lacquer products. It became so well received that during the Qing dynasty the Imperial Palace in Beijing even had a few Yangzhou lacquerware tables, chairs, and plates.
Today, Yangzhou lacquer products are made into over three hundred different forms, including anything from huge standing partitions to coasters to chairs to liquor cabinets. Adding lacquerware into interior design has more or less become a way of making a place look "Asian," and thriving off this, Yangzhou exports this little gem in great numbers to over 50 nations.