Much of the introduction to any writing on the atomic bombing of Hiroshima is going to be dependent on what the paper is seeking to prove. Some introductory elements might focus on the ethical implications within such a decision. Another aspect of an introduction might focus on how historical progression has been significantly changed as a result of the atomic bombing of Hiroshima. The introduction should be linked to what the paper will illuminate in the body of the work.
I think that one aspect of any introduction regarding the atomic bombing of Hiroshima will focus on the human cost. Estimates range between 90,000–166,000 people killed in the atomic bombing of Hiroshima. The data is even more staggering: "Over 90% of the doctors and 93% of the nurses in Hiroshima were killed or injured—most had been in the downtown area which received the greatest damage." Of 2,160 medical personnel in Hiroshima at the time of the bombing, 1,980 were killed or injured. The effects of the bombing were felt even beyond the moment of impact:
Survivor registries include 2,300 individuals exposed in utero. Studies suggest that excess miscarriages and fetal deaths numbered in the dozens, and excess infant deaths (for those exposed in utero) also in the dozens. About 45 cases of microcephaly are known among those exposed in utero, including at least 15 with mental retardation.
Being able to focus on the human cost of the bombing in the introduction of a paper on the topic almost jars the reader in recognition of its historical significance. In discussing the casualty count, it makes clear how the dropping of the atomic bomb carries with it implications far beyond individual calculation. Its brutality is highlighted when confronted with the results of the decision to drop the atomic bomb. Being able to integrate such a reality in the mind of the reader helps to enhance the feel and gravity of President Truman's response.
Well, this depends on what your paper is going to be about. Is it about the horrible aftermath of the bombing or is it about the historical facts on why it occurred?
Either way over the years, my teachers have taught me about 3 different techniques for introduction paragraphs. One would be a question. Asking a question gets people's minds working and thinking, which makes them want to read more to find the answer. You could also use facts and statistics. For this topic it could be how many people had died in the bombing (I can imagine that would be an enormous amount). Lastly, use a scenario. Whether it is about specific person who experienced it or just a description of the event as a whole, creating a scene for the reader will intrigue them and they will want to know more about the topic.
I'm sure there are other ways you could do this, but those are just some that I find to be effective.
The best way would be using your senses in the first sentence. For example, you can use sight to describe the event or have noise that the reader can picture hearing. Then you can continue on with the rest of your introductory paragraph.