First Iron Man Game: Big Mistake!

I ended up playing only those three games, but hey, I did get to play and am having fun reviewing the games in between too much life.

First interesting big mistake in the first game:



I was Black, trying to play mini Chinese, but White did not not agree and played 6 instead of the expected C14, so I punished by playing 7 at C14 myself. White's reply at 8 was labeled 'big mistake' by sendol.

Black can play A or B now, what would be your choice?

I thought it would be best to play A now, but interestingly enough sendol recommended B.



White is quite painful now. This is interesting sequence:



Move 18 is needed to make the hane at 20 sente. If the hane at 20 is omitted, White owns a dead J group. With the hane, the J-group is alive. Quite an important difference.



Expected followup could be like this, and now Black has a severe move to attack the three White stones at the top.



One of the possible scenarios:



More can be found in the sendol review of this game.