When you read the details of Ft Sumter, it appears that the first shot was actually fired on Buchanan's watch.
Buchanan tried to get supplies to Ft Sumter. He used an unarmed merchant vessel, and when the vessel approached Ft Sumter it was fired upon. That, to a lot of us, would have been the first shot of the war.
But it wasn't. The first shots came from the Confederacy as they bombarded Ft Sumter. The Union returned fire. When the shooting stopped, everyone was allowed to leave Ft Sumter. There were no casualties on either side, a fact that I find rather funny.
And as a modern Southerner, I find it funny that a Union cannon blew up during the surrender ceremonies, thus resulting in the first casualties of the new war.
Sometimes history is just plumb entertaining!