Recently I have been playing on Tygem and I have been ending up in these situations where using the estimate button I am forty to eighty points ahead at move one hundred or so, but have like two minutes left on the clock. So far I have been lucky and have only lost once due to sloppy end game play, but I am wondering if there are any good tricks for preparing for these types of situations, where you have a very large lead, but not much time.

When you have a large lead play solid. Give up points. You only have to win by 0.5, so don't try to decimate your opponent and win by 100. Just win. This can be one of the most fun experiences in go. Giving your opponent gains all over the board and laughing because you know it isn't enough for him to win.

Here is an example of one of my games where I did this. The endgame basically started around move 149 and the game went on for almost 100 more moves. I let him reduce all he wanted because I knew I'd won by a considerable margin. I didn't fight his reductions. I didn't try to counter attack. I just made sure my walls were super strong, playing passive connecting moves and backing off to minimize bad aji.



I did make a couple of mistakes. I could have lost my group on the top right - don't know how neither of us saw that. I could have killed his group on the bottom with a throw in - I missed that because of lack of time. Even so, I still would have won.

_________________
"You have to walk before you can run. Black 1 was a walking move.
I blushed inwardly to recall the ignorant thoughts that had gone through
my mind before, when I had not realized the true worth of Black 1."
-Kageyama Toshiro on proper moves

While I agree with this point in endgame, I think this strategy has to be applied with caution in fuseki and middle game. Because too often it leads to overly passive play that brings your opponent back in the game. So I would formulate it negatively: Do not play high risk stuff anymore!