[astrodust]

You do realize that Japan, at the time, was run by a highly militarized government that still carried a lot of tradition from the feudal Japan era. Honour was a massive concern.

Also remember that Japan had already conquered large parts of China and trounced Russia militarily, so they were feeling confident they'd prevail in any conflict with the US. At the time the US was in the middle of a poor economic period and its Pacific navy was in sad shape, many warships were simply relics from WWI. It wasn't exactly threatening.

What Japan didn't realize was that the US would not be bullied, and instead would bite back a lot harder than anticipated.

It's a lot like how America assumed Iraq would be a cake-walk, or Afghanistan could be resolved in a weekend.