Shanghai-based art collector Liu Yiqian recently spent $36.3 million on a tiny porcelain cup with a humble chicken painted on its surface. But for many in China, the most shocking thing wasn’t the amount he paid, or the fact that he paid with an American Express card.

No, it was the fact that Mr. Liu decided to celebrate his Ming-dynasty purchase by sipping some tea from it.

The cup in question is one of China’s so-called “chicken cups,” which were forged in imperial kins and possess a particularly silky texture. Though fakes abound, only 19 genuine articles are known to exist. To art experts, they’re known as the “holy grail” of Chinese porcelains.