Originally posted by benjdm
Japanese bombarded California with submarine in WW2. Can't do much actual damage with a puny little deck gun though.
The Japanese actually killed more Americans (a family of five) when one of their balloons exploded in Oregon.
They launched a campaign of weather balloons with explosive-incendiaries attached and they drifted with the wind over the Pacific with the intent of landing in the Northwest and setting the forests on fire. Didn't work.
All five American civilian casualties in WW II were, however, caused by one of them when they foolishly investigated one that had landed without going off. It did when they messed with it.