It's no wonder the US didn't mint another Purple Heart until 1976. They were prepared for more casualties in the Japanese home islands than the nation saw in all conflicts since, combined.

Similarly in World War 1, over 2700 soldiers lost their lives in combat, on the day the Armistice came to effect.

I wonder why the Japanese chose to open fire.

Probably the same reason why there will always be a debate about the net lives saved/taken with the atomic bombings. The Japanese were indoctrinated to keep fighting regardless of the odds. Plenty of them wanted to fight on even after the bombs were dropped. The fact that it was a hopeless cause was beside the point.

Or, maybe they just had a broken radio and didn't know what was going on. Shame the article doesn't say more about the enemy's motivations.

Yeah right? The bombing of Nagasaki was 12 days earlier, and the surrender shortly after that. So unnecessary.