Japan has the death penalty and they use it.
L
Hanging. And at times, not well executed.
Japan also has a “guilty, but mentally incompetent” verdict that might keep him from the noose.
I was living in Tokyo when Shoko Asahara bombed the subways with Sarin gas. Took ‘em a while, but they hanged every one of those guys.
The criminals have very short notice in advance, maybe a few hours before the hanging. And the outsiders and relatives don’t hear anything until the hanging is over and it is time to go pick up the body.