An opportunity for seki ...
... and I blow it!
Zero9090 (22k) and I were playing a 13x13 during my break. In an interesting exchange in the upper part of the board, I saw a pattern that looked like I could create dual life (aka seki).
So naturally, I instead tried to gouge-out one of the eyes and wound-up losing my entire formation. Very unwise.
I should have played F13 but intead placed my stone in F10.
This was the first time I had encountered a seki position (at least one that I recognized before a blunder) in one of my games. F13 would have resulted in a stalemate for the two interlocked formations.