Why were the Japanese successful at pearl harbour in 1941 but not at the battle of midway Island in 1942?

Pearl harbour was a principal naval base for the Americans and was of paramount importance. The base was strategically placed to protect the surrounding islands and keep ultimate control of the pacific. The continuous expansion of the Japanese Empire meant that it was a growing threat; control in the pacific was more important than ever. Apart from inforcing their control the Japanese would also gain something other than raw materials if they successfully attacked Pearl Harbour. The disabling of Pearl Harbour would lead to vast naval superiority in the pacific.

However, after the attack on Pearl Harbour the U.S fleet was recovering faster than the Japanese expected. The Japanese knew they had to finally finish off the American fleet and take advantage of the subsequent power. They saw the perfect opportunity at the battle of Coral Sea, however the Japanese were not victorious and suffered heavy damages. The wounded Japanese fleet returned home. One month later was the battle of midway and a vital battle for both sides.

Whereas in the attack on Pearl Harbour it was a surprise attack, the battle of midway was not. By the time of the Battle of Midway the Americans had cracked Japan's radio code - eliminating the element of surprise. Another difference that was a crucial factor was the lack of good intelligence reports. The Japanese had formulated plans on the intelligence information they had. The Admiral's plan was firstly to send a large task force to the island of midway, the U.S fleet would sail to protect their island, where a larger Japanese fleet would be waiting to attack them.

Unfortunately for Japan the U.S fleet was much larger than expected, and the Americans already knew about Japan's plans of ambush. Now that Japan had lost six carriers at Coral Sea, and at Midway the Allies could see Japan's grip on the pacific loosening.

The main reasons for the Japanese victory at pearl Harbour was mainly due the element of surprise and overwhelming force. The Japanese also had excellent intelligence which proved was vital in ensuring a victory over the U.S. Conversely the same is true for the American victory at Midway. The Americans were prepared, had excellent intelligence, and surprised the Japanese due to the lack of intelligence on Japans part.