I was reviewing an old game of mine from 2016 - just a few months after I joined OGS around April. I was around 20 kyu at the time and was playing against a 16 kyu. Before I get to the specific VERY BAD MOVE in question (Move 73) I feel like I need to lay the groundwork to really highlight the badness. First, take a look at moves 1-11:
At the time, I naively kept telling myself I was studying SHIN FUSEKI - and that I had the flexibility to play anywhere. The truth was, I had zero understanding of opening priorities (i.e. corner > sides > middle) and what I thought were “networks of stones working across the board” were actually isolated stones that my opponent easily cut apart, then grabbed all the edge potential on the left side.
Ok, so the setup for the really bad move starts at Move 41 where we start a fight for the lower right corner:
I had no idea about joseki, and only a dim understanding of living shapes, but I’d already gained some understanding of how to take advantage of a shortage of liberties, so I did my best to pen White in on all sides:
This sequence of 31 moves took me hours-per-day of reading over a span of probably a week. I was so proud of myself for not only creating the potential for two living groups on either side, but - IF I could surround White’s dragon pointing into the middle, I could get it to close up the false eye at S4 and eventually kill the entire group!.
And then, after all that time, and thought, and effort, I played P12 instead of settling the lower right stones. White played on the Q9 key point - where I should have played.
White ended up capturing those initial 7 stones, plus another 5 stones I sacrificed trying in vain to save that group.
Looking back now, I realize that I could have saved all those stones by just playing R8 after White played Q9, but at the time time I got frazzled and messed it up. Talk about learning my lessons the hard way.