The earliest known steel acupuncture needles in the world have been discovered in the archaeological wonderland that is the tomb of the Marquis of Haihun in eastern Chinas Jiangxi Province. With a cross-sectional diameter of only 0.3-0.5 mm, it is comparable in fineness to modern acupuncture needles and attests to the high level of metallurgical technology in the Western Han Dynasty (202 B.C.-220 A.D.).At least five needles were found in a gilded lacquer box placed in the inner coffin of the deceased, Liu He, the disgraced 27-day emperor who was later re-enobled with the title Marquis of Haihun. He died in 59 B.C. and was buried with tens of thousands of artifacts, two million bronze coins, a librarys worth of books on wood and bamboo, numerous weapons and a set of fish scale armor of unprecedented complexity.The needles, likely wrapped in cloth, now decomposed, had been inserted into a hollow jade tube. When archaeologists opened the lacquer box, they found the broken jade tube and what looked like needles inside. They were corroded and fragmented, giving researchers the opportunity to analyze small fragments that had already broken off instead of taking samples from the larger sections.Tests confirmed the needles were made of steel created through an advanced frying process that made it possible to achieve their extraordinary thinness. Their identity was confirmed by a wooden label found near the box inscribed Nine Needles Complete.This definitively identifies them as one type of the Nine Needles described in ancient medical texts, explained Wang Chuning, a doctoral researcher at Peking University, according to Xinhua News Agency.The significance of this steel innovation was emphasized by experts.Iron needles rust easily, risking infection. Gold or silver needles are too soft and difficult to make this thin, noted Zhou Qi, a research fellow at the China Academy of Chinese Medical Sciences, adding that steel needles enabled more sophisticated techniques and longer retention in the body, representing a major leap from stone or crude metal tools.This is the earliest physical evidence of steel medical needles in China, Gu Man, director of the China Academy of Chinese Medical Sciences, told the Global Times.