May I have a stronger player's opinion about an exchange I made in a game?

I just finished a correspondance game against a 1k player. Needless to say, I was overwhelmed, and I’m not so greedy with other people’s time that I’ll demand a full review of a stronger player.

What I do want to know about is a sacrifice play I made just before I resigned:

The sequence began when white chose to connect his stones at H17. Move 128. After this move, I saw potential to use the shortage of liberties for the white group to turn the seki in the top left into a living corner by sacrificing 11 stones. In the game, this lead to my defeat, since in addition to sacrificing those stones, I built white up against my other weak group in the other corner, and I reasoned it would be impossible to continue play, hence my resignation.

Here are my three questions about the exchange:

1.) first off, was I even right about the top left corner becoming seki? Was there some way for black or white to kill the other outright without the sequence? I thought my opponent had played a bad move in the joseki for that corner, but he followed it up with a play I’d never seen before, so it became a confusing mess for me.

2.) Did white make any mistakes responding to black after move 128 that made the exchange possible? Basically, did I misread and my opponent blunder? Or was white’s play optimal up to that point.

3.) I know that in this game the exchange wound up strongly favoring white, but assuming an empty board, was the sacrifice of the 11 stones for the corner even? Or in that case would it still favor one player over the other?

thanks for listening to my problems. XD I’m open to any discussion or criticism about any part of the game, but I don’t want to trouble anyone.

  1. There’s ko aji if Black throws in, but the disadvantaged player (White) has the opportunity to prevent it in gote as the liberties are filled. So it’s basically seki.

  2. After move 128, there was no way for White to do much better in terms of result. Throwing in against the two stones on the top would reduce the number of liberties and introduce a very unfavorable ko, but it has its own costs. Still probably better.

  3. What do you mean by an empty board? This tactical shape consumes about a quarter of the board as it is. Anyway Black gets more cash in excess of White’s with the sacrifice instead of the connection, to the tune of more than 20 points, but White connects the groups and seals on the outside. This is quite powerful. On an ‘empty board’ it would be far more important to develop the outside rather than fiddle around with converting an interior seki and saving 6 other stones while getting even worse on the outside in gote.

IMO the problem in the upper left was at move 49. If you had cut at F17 white would have collapsed. White’s move at E17 looks like an overplay.

to severence: I suppose by “empty board” I meant a situation where the events in the top corner wouldn’t have had a significant effect on stones elsewhere, but I see what you mean. the size of the fight alone makes that a pretty silly thing to ask about.

to vincent: huh, I read it out, and it looks like you’re right. I shouldn’t have let myself panic at the aggressive play. XD

thank you both for your input.