That’s a popular quote, but there’s not a shred of evidence Yamamoto ever said it. Ditto the Hitler quote about Germany’s gun law.
A lot of what passes for Ben Franklin and Abe Lincoln quotes are questionable, at best. Even if he never said it though, it’s the truth. No society in the history of mankind was or is anywhere near as well armed, not even the Swiss.
Well, they ought to have said it.
That turns out not to quite be the case. Second hand report with known chain, originating with JMSDF officer on joint manuevers, around 1960, with US Navy. Attribution as to approximate year and the US Carrier the exchange took place on.
Armed citizens: the deterrent factor
If you're not going to believe Massad Ayoob, who are you going to believe?
Not a direct quote from Yamamoto, but an account of the feelings of the Japanese Navy of WW-II.