What is the connection between the lethal fugu fish at the beginning of the story and the detailed description of the fish in the soup served at supper?
I think that one of the connections made between both is that food preparation is linked to death. The children realize that the mother's death was the result of eating the poisonous part of the fugu fish. The detailed description of the father preparing the fish for dinner is reflective of a couple of elements. The first would be whether or not the father is seeking to do with his family what his business partner did to his. In the face of failure, Japanese tradition embraced suicide as a way of "saving face." The death of his wife, the estrangement of his kids, and the lack of success present in the family might lead one to believe that the father is preparing food to accomplish what his business partner did to his own family. On the other end of the spectrum, the preparation of food might be a step towards the father seeking to rebuild his life after his wife's death. The fact that he can prepare his own food and be more autonomous could be an advance towards a new life, one that is outside of traditional contexts. Accordingly, the connection between both examples of food preparation could be representative of how those of the modern setting have to end up using the past as prologue for an improvement in the present and the future. The father's detailed preparation of supper might be an example of where the past is meant to serve as an example of how the future can be better. This might be where the ultimate connection between both is seen.