This is discussion archived from a time before the current discussion method was installed.
Morgan Wick: It's not entirely clear what the "diagonal" is all about.
Looney Toons: I hope I've clarified it for you.
KF: I'm pretty sure this one is actually one of The Oldest Ones in the Book on account of Excalibur achieving the effect in some version or another of the legends. C/D?
Looney Toons: I'm inclined to discount that, as this is a primarily visual trope — otherwise any tale where a sword cut through something would count.
J Random User: Well, my reading is that the crux of the trope is the pause before realizing that the single slash was a deadly one...
Susan Davis: Hey, wiki, Underworld is already in the list; we don't need it twice.
Aerin Pegadrak: Noticed that one too. BAHLEETED!
Citizen: I tried going for a smaller, better picture (pre-Crash), but it's still not an optimal demonstration of a diagonal cut...
Neenee: So... what exactly makes this one different from Clean Cut? Being diagonal, having delayed effects, or being Japanese? According to the entry of Clean Cut, it's being Japanese, but that aspect is barely mentioned here...
Does Makuro from Yu Yu Hakusho count, with her ability to actually slice space itself? Those cuts do about the same thing as the Diagonal Cut, they are diagonal, and they do that famous anime-glowing-white thing...
