[ARC5] How the U.S. Cracked Japan's 'Purple Encryption"

[Jim Haynes]

I wonder how much Japanese religion had to do with it.  If you believe
the emperor is a god then you might expect a miraculous victory over
a stronger opponent.  But maybe Yamamoto didn't believe that.

I've also read that Japanese naval strategists believed in a repeat of
their success in the Russo-Japanese war of 1904-05.

And the strength of isolationist politics in the U.S. may have emboldened
both Germany and Japan.