At the annual conference of the Chinese Agricultural Association held in 1944, Needham gave a speech and declared that gunpowder originated from the alchemy in Han dynasty, while he, however, deliberately altered the text of the speech later in 1948 and proposed the theory of the origin of gunpowder in Tang dynasty. Through a comparative analysis of several related studies that emerged during the initiation and development of the modern historiography of gunpowder, it was found that Needham's theory about the origin of gunpowder was an inheritance and development of the doctrine of Chia-sheng Feng (Feng Jiasheng 冯家昇). However, both Feng and Needham lacked sufficient evidence to substantiate the dating of the related alchemical texts, which has resulted in an unstable academic foundation for the theory of the origin of gunpowder in Tang dynasty. Nevertheless, the theory was logically consistent with the Needham's Grand Question.
Wang et al. (2024) studied this question.