Don't fuck with blades when you are twisted on GIN.
刃 is basically sword, which is bisecting a little line, which we'll think of as a FINGER for the purposes of the following mnemonic:
BOOBOO: not a knife or sword - the BLADE or the SHARP EDGE of one. Remember, swords don't kill people, 刃s kill people.
Blade comes from the SWORD radical, which makes sense.
'Round' comes from 9, which has a HOOK on the right side. (the right side of blade turns outwards).
So you can say, "I can hang nine round donuts on the HOOK."