On 12 August 2009 Ai Weiwei is due to testify in favour of Tan Zuoren, the activist who published the enquiry into the death of over 5,000 schoolchildren during the earthquake. On the eve of the trial, in Chengdu, he is woken up by the police in his hotel room, questioned and beaten, thus effectively preventing him from testifying at the trial.

On 16 September 2009 while setting up his exhibition entitled So Sorry in Munich, he suffers a brain haemorrhage, probably caused by the beating, and is rushed to hospital for an emergency operation. His MR becomes Brain Inflation.