A US prosecutor’s newly revealed diaries from World War II have laid bare the gruelling effort to document Japanese wartime atrocities in China and the unlikely bond forged between him and the people he helped. The diaries belonged to David Nelson Sutton, an American assistant prosecutor at the Tokyo Trial, or the International Military Tribunal for the Far East – a landmark international judicial effort. The tribunal drew upon a vast “evidence wall” comprising nearly 50,000 pages of trial...