Photographs taken by Joseph Needham on visits to various locations in Szechuan (Sichuan) province 四川省 and in Chungking (Chongqing) 重慶市, where he was based, first in the British Embassy and then purpose-built offices for the SBSCO. The numbering (SZE 1-12) indicates that there may originally have been 12 rolls of film, but SZE 11 has never been found. The films and their photographs were not originally labelled in strict chronological order. Some sections of the negatives have not been developed because there are no images on the negative or because any images present are severely damaged or indistinct. No entry has been made for these.