The Emperor’s Grand Inception, and the defeat of the Grand Clerk

We now turn to the story of the great reform of the system of celestial calculation, li, that took place in 104 BCE. The decision to carry out a reform was driven by the emperor’s obsession with finding a way to escape death by becoming an ‘immortal’. The official astronomer, Sima Qian, appears to have been pushed aside in favour of experts drawn from outside the bureaucracy. Once the reform was concluded, disputes did not cease. Around 78 BCE it was claimed that the system set up in 104 BCE was fundamentally flawed. For the first time we see a detailed account of the use of systematic observation of the heavens to provide a basis for deciding whether a system of celestial calculation was correct. Finally, we examine attempts made under the late Western Han to give an account of how such calculations were made in past ages.