I am a Japanese language teacher. There is a class called “Let's introduce the buildings in your country to everyone in Japanese!” Today in this class, the youngest student, a Vietnamese man, gave a presentation about a historic prison. I have taught this class many times before, but this was the first time when a student give such a presentation about prison. This prison is where many Vietnamese died during war and invasion. I hadn't known that prison and its history until his presentation. When his presentation was over, another Vietnamese student said, "Teacher, we want to see a video about this prison. I want you to watch a video with Japanese subtitles!" Then we watched the video she found together with students from other countries. The video showed how many Vietnamese people starved to death or were tortured in prison. After about 10 minutes, another Vietnamese student said, "Teacher, that's enough. Can you stop the video?" Then I noticed that all the Vietnamese students had gloomy looks on their faces, and I became very worried. Until I saw their gloomy faces, I had thought that the Vietnamese students wanted everyone to know about the history of their country, so I agreed to let everyone watch the video. But I wondered if it was the right way. After the class, I asked my Vietnamese colleague, a Vietnamese interpreter, what common understanding Vietnamese people have about the history of the prison because in Japan too, there are historical stories and places that are considered taboo in public place. At the end of the class, I asked the interpreter to asked the students, "Do you think it was a good experience for you to watch this video? The teacher is worried about that." The students replied with a smile, "There's no problem. Don't worry!" I still don't know if watching that video was the right decision or not.