I'm sure you're right that there are chopping techniques that wouldn't cause this problem. But I've tried to develop them before, and find myself gradually falling back into old habits sooner or later. I was very careful with onions for several years after the 2009 incident, but last night shows that it didn't last forever :-/ So a technological fix seems more likely to be reliable, in my case.

Fair enough. I really like mandolins for cutting rapidly and evenly, but if you catch yourself on them they are a lot more vicious than knives. Brilliant for when you have to cut 3kg of cucumbers for pickle or a buffet, though.

Also, once you have a mandolin you can claim to be a freedom fighter (http://www.youtube.com/watch?v=KXKa3H-jREM) (music).

What's your onion-chopping algorithm? I've had fewer mishaps since I started leaving the root end on the onion right up to the end of the process, since it holds the various layers together.

Hmm, I don't think I've tried that.

I was also wondering about turning the half-onion over so that I'm cutting into the flat side rather than the sloping side that a blade can slide down.

However, since I'm trying to reduce my accident rate from a current level of one every few years, it might take a while before I find out whether a new technique really helps, or just feels as if it stands to reason that it ought to :-)