When I was doing history in Year 11 & 12 (junior and senior?) I had this incredibly strict, serious teacher. He was known throughout the school for his intensity, and his lack of tolerance for bullshit. When we covered the Rape of Nanking, he had gone through and sharpied out a paragraph on a handout. He told us that he wouldn’t normally try to shield his students from a part of history, but that this particular part was incredibly distressing.