went to club last night -- first time in I don't know how long -- played a game with a kid who said he was 15kyu from not playing in a long while. When I asked him what his level was before he quit playing -- 8kyu
with almost every move, I think he played out the whole game in his head.
then we'd get to a move that he realized was not so good, either as soon as he played it, or a few moves later. He wanted to go back an examine it just to see "what if". I said sure -- my first mistake!!
now, I normally don't care if he wants to take back a move and replay from there. I don't mind losing. Its just a social club game. But after we mostly filled the board he wanted to go back to his original move.
We did that a couple of times, and almost every time there seems to be an extra black stone on the board after the restoration (I was white).
after almost 3 hours, it felt like I played 3 or 4 games in one, and lost most of them.
next time -- game clock, 20min per. no undo. and definitely no variations during the game -- you don't get to see what my plans are until I'm ready to play them. During one of the variations, I sprung a trap I was holding onto -- the variation had gone so far, I didn't think he'd be able to restore the original board position -- later, during the "real" game, he was now prepared for the trap.
he may have been off his 8kyu just a bit, but certainly not 15kyu worth. And I think he gained 3 stones in strength during our one(five) game(s).