Good question. In consideration of their actions I think they had a rather prudent naval campaign strategy albeit doomed. They atacked Pearl harbor to deprive the US of a Pacific operating base thereby protecting their western Pacific expansion, particularly their access to Dutch East Indie oil.
Midway was aimed at depriving US submarines their re-fueling depot without which they could not reach the sea of Japan. Without Midway eastern Japan would be at the extreme limit of US sub range.
It most part it was the US subs which destroyed the IJN’s ability to operate in the Pacific, making island hopping feasible.