Lost near the end

tekesta · #1

Here I played against a 15k player on OGS. I was doing well until late in the game when a semeai developed in the top left part of the board and I did not read it out correctly. (Probably should have neutralized D14 and E14 Black stones by playing at F13 when I had the chance.) Needless to say, I lost by 11.5 points. Much obliged in advance for your comments.

Joaz Banbeck · #2

My initial reaction is that you over-focus on one small part of the board at the expense of larger moves elsewhere.

Examples:
Move 32 is really solid shape, so it is hard to dislike it, but the lower half of the board is wide open
Move 34 is simply overconcentrated when the lower half of the board is still open.
Moves 86, 92 and 94 were all small when S18 is huge.
Move 124 is one point gote while P1 is four point sente. ( it is late, so my count may be off, but the principle still applies )

ez4u · #3

Let's look at the end of the game. It has a variety of interesting lessons. First Black cuts at 1 below and White played the atari at 2. But consider the two groups of marked White stones. Which is stronger and how do we tell? The four stones in the center have three liberties and the cutting point at 'b'. The thirteen stones on the left have six liberties and extend all the way to the side. Realize that the left-side stones are much stronger. White should atari at 'a' instead of at 2 = play from your weaker stones. (We will skip the discussion of White playing elsewhere. I am certain that over confidence has lost more games than any other issue.

)

Click Here To Show Diagram Code: [go]$$Bcm1 $$ --------------------------------------- $$ | . X . O . . . . . . . . . . . . . . . | $$ | . X O . O . . . . . . . . . . O X X . | $$ | X . X O . X . . . O . . . O . O O X . | $$ | . . X O . O . . . , . . . . . O X X . | $$ | . X X O . O . . . . . . . . O X . . . | $$ | X X O X X . . . . O . . . . O X X . . | $$ | X O O . . . . . . . . . . . O X . . . | $$ | O O . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . O . . . O O O X . . | $$ | . . . O . a . . b O . . O O X X . . . | $$ | . . . . 2 1 @ @ @ X O O X X . . X . . | $$ | W W . . . W X @ X X X X O X X X O O . | $$ | X W W . . W X X . . . X O O X O X . . | $$ | X X W W W W X . . X X O O O O O X . . | $$ | . X X W X W X . X X O . O X X X X . . | $$ | . . . X X W X X . O O . O X . X . . . | $$ | . . X . . X X O O . . . O O X . . . . | $$ | . . . . . X O . O . . . . O X . . . . | $$ | . . . . . X O O . . . . O X X . . . . | $$ ---------------------------------------[/go]

If play continues like this, Black has two liberties and will never get any more. Black might as well play the hane in the upper right and the game ends quietly.

Click Here To Show Diagram Code: [go]$$Bcm1 $$ --------------------------------------- $$ | . X . O . . . . . . . . . . . . . . . | $$ | . X O . O . . . . . . . . . . O X X . | $$ | X . X O . X . . . O . . . O . O O X . | $$ | . . X O . O . . . , . . . . . O X X . | $$ | . X X O . O . . . . . . . . O X . . . | $$ | X X O X X . . . . O . . . . O X X . . | $$ | X O O . . . . . . . . . . . O X . . . | $$ | O O . . . . . . . . . . . . . O X . . | $$ | . . . . . . . . . O . . . O O O X . . | $$ | . . . O 4 2 . . . O . . O O X X . . . | $$ | . . . . 3 1 O O O X O O X X . . X . . | $$ | O O . . . O X O X X X X O X X X O O . | $$ | X O O . . O X X . . . X O O X O X . . | $$ | X X O O O O X . . X X O O O O O X . . | $$ | . X X O X O X . X X O . O X X X X . . | $$ | . . . X X O X X . O O . O X . X . . . | $$ | . . X . . X X O O . . . O O X . . . . | $$ | . . . . . X O . O . . . . O X . . . . | $$ | . . . . . X O O . . . . O X X . . . . | $$ ---------------------------------------[/go]

A little bit later plays 1 and then 3 below. I think that 3 is interesting because to me it says that White has difficulty recognizing important versus unimportant stones.

Click Here To Show Diagram Code: [go]$$Wcm1 $$ --------------------------------------- $$ | . X . O . . . . . . . . . . . . . . . | $$ | . X O . O . . . . . . . . . . O X X . | $$ | X . X O . X . . . O . . . O . O O X . | $$ | . . X O . O . . . , . . . . . O X X . | $$ | . X X O . O . . . . . . . . O X . . . | $$ | X X O X X . . . . O . . . . O X X . . | $$ | X O O . . . . . . . . . . . O X . . . | $$ | O O . . . X . . . . . . . . . O X . . | $$ | . . . . 1 2 X O . O . . . O O O X . . | $$ | . . . O 3 X O . O O . . O O X X . . . | $$ | . . . . O X O O O X O O X X . . X . . | $$ | O O . . . O X O X X X X O X X X O O . | $$ | X O O . . O X X . . . X O O X O X . . | $$ | X X O O O O X . . X X O O O O O X . . | $$ | . X X O X O X . X X O . O X X X X . . | $$ | . . . X X O X X . O O . O X . X . . . | $$ | . . X . . X X O O . . . O O X . . . . | $$ | . . . . . X O . O . . . . O X . . . . | $$ | . . . . . X O O . . . . O X X . . . . | $$ ---------------------------------------[/go]

I would play 1 below instead of the previous 3. The reason is that the two marked stones are important for destroying Black's eye shape. As long as we preserve those two, Black can not make an eye by capturing E9 so there is no need to protect against Black's 2-6.

Click Here To Show Diagram Code: [go]$$Wcm1 $$ --------------------------------------- $$ | . X . O . . . . . . . . . . . . . . . | $$ | . X O . O . . . . . . . . . . O X X . | $$ | X . X O . X . . . O . . . O . O O X . | $$ | . . X O . O . . . , . . . . . O X X . | $$ | . X X O . O . . . . . . . . O X . . . | $$ | X X O X X . . . . O . . . . O X X . . | $$ | X O O . . . 1 . . . . . . . O X . . . | $$ | O O . . . X . . . . . . . . . O X . . | $$ | . . . 3 O X X O . O . . . O O O X . . | $$ | . . . W 2 X O . O O . . O O X X . . . | $$ | . . 5 4 O X O O O X O O X X . . X . . | $$ | O O . . 6 W X O X X X X O X X X O O . | $$ | X O O . . O X X . . . X O O X O X . . | $$ | X X O O O O X . . X X O O O O O X . . | $$ | . X X O X O X . X X O . O X X X X . . | $$ | . . . X X O X X . O O . O X . X . . . | $$ | . . X . . X X O O . . . O O X . . . . | $$ | . . . . . X O . O . . . . O X . . . . | $$ | . . . . . X O O . . . . O X X . . . . | $$ ---------------------------------------[/go]

Finally let's look a little further ahead. White plays 1 below and Black answers at 2, making one eye. (White 1 at G13 might have given Black less scope for action but it should not have mattered.) Now White has to make sure that there is no second eye. White 3 is effective to prevent a second eye. (H12 might have been better by leaving fewer cutting points.) When Black plays 4, however, White played 'a' and things went downhill rapidly. The important point to realize is that 3 is the key stone and is sufficient to kill Black - there is nowhere for Black to make a second eye. If White understood this, quietly pulling back with 5 would come naturally and the game would be effectively over, W+.

Click Here To Show Diagram Code: [go]$$Wcm1 $$ --------------------------------------- $$ | . X . O . . . . . . . . . . . . . . . | $$ | . X O . O . . . . . . . . . . O X X . | $$ | X . X O . X . . . O . . . O . O O X . | $$ | . . X O . O . . . , . . . . . O X X . | $$ | . X X O . O . . . . . . . . O X . . . | $$ | X X O X X X 1 . . O . . . . O X X . . | $$ | X O O . . . 2 3 5 . . . . . O X . . . | $$ | O O . O X X . 4 a . . . . . . O X . . | $$ | . . . . O X X O . O . . . O O O X . . | $$ | . . . O O X O . O O . . O O X X . . . | $$ | . . . . O X O O O X O O X X . . X . . | $$ | O O . . . O X O X X X X O X X X O O . | $$ | X O O . . O X X . . . X O O X O X . . | $$ | X X O O O O X . . X X O O O O O X . . | $$ | . X X O X O X . X X O . O X X X X . . | $$ | . . . X X O X X . O O . O X . X . . . | $$ | . . X . . X X O O . . . O O X . . . . | $$ | . . . . . X O . O . . . . O X . . . . | $$ | . . . . . X O O . . . . O X X . . . . | $$ ---------------------------------------[/go]

By the way, 180 should have been at G16. See if you can confirm that Black can not make a second eye after that!

Uberdude · #4

Oh dear Lord, what a horrendous end to the game! In addition to ez4u's excellent points I would also say that in response to the cut you could quietly play h11 to make good shape and fix the cut*. Then you can pass if Black does something with his stone, or answer if you feel like being safe (capture e14 would be a good idea to take care of your other weakness). You don't need to fill his liberties for him to be dead: just take care of your weaknesses, surround him (he already is) and make sure he doesn't make two eyes.

*that doesn't actually work.

To expand a bit more on the way to approach such a nonsense cut:
- First identify your weaknesses, are there any of your stones in danger which if he captures he lives? In this case it's those 4 stones with only 3 liberties.
- Look for other cuts/cutting stones, in this case e14 ones. If he can connect his cutting stone to those then your left side group would be cut off and need to make 2 eyes (it can probably make 4). The other thing to check is can he separate a12 from a8 groups. The answer which doesn't need much reading to verify is no, even without the d10 stone if you keep passing and he gets stones at f9,e9 and c9 then you can still connect at b10 (or even pass again as he still can't cut you with another move. However you should note that if you do connect on the 2nd line like this then you are losing eyeshape, so if black can save the e14 cutting stones and press you down like this (which would require passing a few times in succession) you could have some trouble.
- Does he have enough space to make two eyes? No way jose! If you've played the living/killing game of an empty board but for one colour round the first line then you know that it is hard to live in a 17x17 space if the opponent has no weaknesses. This space isn't even 7x7.
- So the gameplan? Make sure the 4 stones don't die, make sure he doesn't save the e14 stones (actually not so essential, you can let him make a bigger dead group if he wants), keep connected, and pass the rest of the time as he futilely fails to make two eyes in a tiny space.

Lost near the end

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