Soon after Pearl Harbor Tokyo was bombed and they lost the battle of Midway; Yamamoto was right that they had to win in six months, or they would lose.
The Japanese were impressive for a 1930s army; they were completely outclassed in the 1940s. They looked all the more impressive because the Allies decided to finish off the Axis in Europe first. Even many of Australia’s troops were fighting the Germans in North Africa, leaving the US to defend Australia.
One thing people should realize is the reason Japan took the risk. Japan has few mineral deposits to support their industry. They went after Australia for that very reason.
Currently, China is going full-tilt to lock up minerals world-wide. If they can make the case to Japan that they can replace the US in that regard, at a substantial savings, we would face a huge military and status loss of enormous proportions. Japan is tired of their 10-15 yr recession, I’m sure. Their natural aggression may be running out of patience.
Japan’s military had many problems during the war that were never overcome. Their army had spent years expecting to fight the Russians in the wastes of Siberia, and had honed their fighting skill against a fairly ragtag army in China. In addition, they were heavily dependent on advance intel and scouting before mounting an attack, and had a difficult to impossible time changing plans once the attack had begun and circumstances had changed. In addition, there was no concept of a joint command between the Imperial Army and Imperial Navy.
The Japanese had spent years doing recon of East Asia and Hawaii before launching the successful attacks (against fairly modest peacetime armies) of 1941-42. Once the advantages of surprise and advance scouting were gone, and they were projected into the jungles of the southwest pacific and atolls of the central pacific, they were quite literally out of their element. They fought very well, but without the ability to live off the land (as they had done in China) and effect resupply, they were doomed.
As to the events of Pearl Harbor, as an anonymous Freeper said some years ago, some people just don’t want to accept that, on a sunny morning in 1941, the United States was caught with its pants down.
I think a better way to regard the Japanese Army is that, of all the participants in World War II, they were the only one that had not learned the lessons of World War I. On many levels, from their rifles to their uniforms and tactics, they were reminiscent of a pre-1914 European army.