The first question many people will be asking is what was the gun used and how did the shooter get hold of it?
The answer appears to be that he may have built it himself. Photographs taken as the suspect was being apprehended show what looks like an improvised, or home-made, double-barrelled shotgun.
Gun violence is very rare in Japan, and guns are extremely difficult to own. Political violence is also extremely rare.
Mr Abe did have a team of security police with him. But it appears the shooter was still able to get to within a few meters of Mr Abe without any sort of check, or barrier.