According to the director, he has been holding in-depth discussions with the creative team since September 2016. The Chinese team, including the composer Tang and conductor Lyu, visited him in London and they "spoke every day for several months, for over three hours a day".

"We are dealing with a man's diaries. During our long discussions, we agreed that we cannot make an opera about a diary, but we can about the story. What was happening in Nanjing at that time? What were the Japanese intending to do? The theme of the opera is about compassion. We give a voice to the suffering of the Chinese people, not just about Rabe," the director says.

In the production, the stage is framed by Nanjing's city walls, which helps to create a focus for the performance, and adds human scale. "The walls are also symbol of the city, which bore witness to history," he adds. Other landmark buildings such as thepost office are also represented in the set design, to remind audiences of Nanjing during that era.

"I feel honored to have composed this opera since this subject is so important to Chinese people. Unlike many of the operas I've worked on before, this opera has been quite challenging and I spent a year working on it. As well as the suffering and anger of the Chinese people, I wanted to express a longing for peace and love through the music," says Tang, who is the director of the composition department at the Central Conservatory of Music in Beijing. The theme music for the opera was based on Johann Sebastian Bach's Passacaglia and Fugue in C minor, which is combined with elements of folk music from Jiangsu. To open and close the opera, Tang wrote solo violin pieces to indicate the initial misery and the prospect of a brighter future.