The less classy approach which I came up with the other day: somehow convince your opponent that their bent-four in the corner (with two of my stones in the middle of it, even) was in seki and should count as alive. Not only did I give them an odd sort of victory, I gave them a source of confusion that could last for who-knows how long!

(This was not, to be clear, intentional mendacity--I was convinced too. I like to think I know better! Oops. Such are the hazards of ddkville.)

Hi amb,

Were you then and are you sure now it was indeed bent-4 and not seki ?
In SOME cases, the two are off by just one stone!