At the end of the 1950s,Sun Yingzhou considered that the ’chazi’(damaged colour)on Chenghua doucai imperial porcelain as a defect was originally produced in firing process during Chenghua period(1465―1487).Researchers in China have accepted his view.But any fragment with the ’chazi’ has never been found in several tons of Chenghua imperial sherds excavated from Ming imperial kiln site in Jingdezhen.In China,few scholars have questioned the formation of ’chazi’,and further investigated scientifically.The researchers at the Research Laboratory in the British Museum,employing unde-structive EDXRF,have analyzed the chemical composition of the ’chazi’(damaged colour)on a Chen-ghua doucai stem cup in the museum,and they have confirmed that the ’chazi’(damaged colour)was caused by the fire of the Jianfu palace in the Forbidden City in 1923.Based on their research,the authors studied the colour chemical principle of the ’chazi’s’ formation carefully.According to the ceramic technology principle,scientific reasoning for the ’chazi’ was carried out.With the help of the history of Qing court,the brainteaser of the ’chazi’ was totally uncovered,the misunderstanding for the ’chazi’ has also been corrected.The research also suggests that employing modern science and technology is a direction to study Chinese ancient ceramic further. At the end of the 1950s, Sun Yingzhou considered that the ’chazi’ (damaged color) on Chenghua doucai imperial porcelain as a defect was originally produced in firing process during Chenghua period (1465-1487). Researchers in China have accepted his view. But any fragment with the ’chazi’ has never been found in several tons of Chenghua imperial sherds excavated from Ming imperial kiln site in Jingdezhen. China, few scholars have questioned the formation of ’chazi’, and further investigated scientifically.The researchers at the Research Laboratory in the British Museum, employing unde-structive EDXRF, have analyzed the chemical composition of the ’chazi’ (damaged color) on a Chen-ghua doucai stem cup in the museum, and they have confirmed that the ’chazi’ ( damaged color) was caused by the fire of the Jianfu palace in the Forbidden City in 1923.Based on their research, the authors studied the color chemical principle of the ’chazi’s’ formation carefully. According to the ceramic technology princi ple, scientific reasoning for the ’chazi’ was carried out.With the help of the history of Qing court, the brainteaser of the ’chazi’ was totally uncovered, the misunderstanding for the ’chazi’ has also been been corrected. research also suggests that employing modern science and technology is a direction to study Chinese ancient ceramic further.