Sub-page of TsumegoFromGames70

Tamsin's attempt and variations

[10] White to move  

tderz: I have to admit, that this simple - even more obvious - move did not occur to me during the game.
I was in byoyomi, just knew 'something has to work here' and gambled.

[20] White to move  

[30] Life  

tderz: It seems that W cannot avoid B's life.
Black connects at W1 after W captures 4 stones with W7 at a.
Black has made there 2+2 = 4 points (m+n+2xW1);
hence lost 10-4 = 6 points in comparision to dia. [32] below.

Correction by Bill:
White made 11 points by capturing in total 5 black+circle (to the hat-shaped black+circle, the points of black+circle next t and t itself have to be added)

the net result seems to be 6+11 = 17 points,

which White snatched away (in Gote).[1]

W cannot avoid B's life in either variant and
Black has nothing to chose either (except life or death).

This variation (here, dia. 30) is better than that of dia. 100,
because Black has to give up the stone to the right of W5 (compensates for that White catches B 5 stones in dia. 100 below),
which then additionally gains the point t for White..

[33] 7 points net for White  

Bill: After W7 (white+circle) Black gets 4 points locally, but White gets 11: net 7 for White.

tderz: Yes, thanks Bill, the 3 points around white+circle have to be added to the score of White. (During writing I thought once about that, than forgot it over all these diagrams).
My scoring however takes a maximum territory of 10 for Black and zero for White as reference.

[32] Life with Maximum Territory for Black  

tderz: Maximum Territory for Black
After a connection at black+circle,
Black would have had 10 points (thanks to Bill for pointing that out),
as a White threat at a
could be answered safely by black b even if liberty e is gone.
(White c? -> black d).

[34] No protective play  

Bill: I believe that Black has 10 points after black+circle. He does not need a protective play after White fills at white+circle. For instance, through B6 Black is alive. (W5 and B6 are miai.)

Bill: That makes the original position worth 1.5 (for Black), and a gote here gains 8.5 points. I expect that this play was sitting around for some time. :-)

tderz: I never meant that Black needs protective play in dia.[32] above, even if liberty e is taken.
Only if e and a are both taken, than Black has to react and still can live with b.
This should have been clear from my text. I am simply bad at counting,even until 10.

Bill: Since black+circle eliminates the immediate snapback threat, I thought it was worth showing this variation, no matter what you had in mind. :-)

Anyway, this shows that you don't have to be good at counting to be good at go. :-)

[40] How to continue ?  

nando: I must be missing something (again): what is the sequence after this B2 ?

tderz: something similar to dia. [30] occurs:

[50] transposition?  

tderz: after B2 White must go for the snapback with W3,
Black has time to atari white+circle with B4,
White can complete the atari-snapback with W5,
yet cannot connect at a in order to kill (damezumari),
only capture with b.
Hence, Black lives.

My question to you and Tamsin: 'What's best?'

nando: if B4 at W5 instead, I still can't see the light... Must be a blindspot of mine.

[60] transposition?  

tderz: Aaah so-desne ... get your free experience of ...
see yourself.
Black cannot give atari at b for a living shape, neither squeeze at c (auto-atari).
In fact, a large double-snapback at d threatens.
However, if Black defends against the snapback,
White kills by making bulky-5 with atari at b.
Black is doomed either way.

nando: Thanks. Indeed, a blindspot of mine (W7)

[70] double-snapback  

tderz: this the double-snapback threat

[80] bulky-5  

tderz: this is gomoku-nakade

tderz: Tasmin, that looks very good to me for the 1st move! How much time did you need for this? I move this to the solution page, however, could you please reply to the questions below and edit for the best sequence for both?

How would you then answer the question:

  • 'Is this an L&D- or an endgame problem?'
  • What are the best moves for both?

(locally, as Black will lose the game anyway if he loses already only some points)

Tamsin: Hi, the move I gave was the second one I considered, as initially I looked at 3 in Diagram 10. It took me about a minute to see my suggested answer. Normally I pretty quick at spotting initial moves, but I'm trying to train myself to read through variations properly.

I'd say it was likely a L and D problem. Certainly, I would want to read it out during a game so that I could know its status and then act accordingly: if White cannot kill for now, she may be able to use the aji.

I don't know yet the best moves for both. Reading all variations is much harder than spotting a likely killing move and playing it on a "percentage" :-)

Tamsin, I completely agree with you about the complexity of complete reading and spotting vital points.
Actually, I started with W3 in dia.[10] as first move (sequence as in dia. [90] below).
In the game, where I was already in byoyomi.
I was quite shocked when my colleague/friend (2k) gave me W1 in [10] as answer when I posed the position to him, because I thought that I 'missed the kill'.
However, now I am convinced that W cannot kill Black (at best play for both), hence it's an endgame involving L&D-problem. (the answer to my question)

[90] actual Game sequence - Inferior?  

tderz: evaluated this sequence here on on November 22, 2006 - 21:15 as 'inferior'.

Bill: C'etait moi. I have been posting on this page anonymously. I recently installed Linux, and lost my cookies, which would have identified me on SL.

tderz: D'acc, compris. Et en plus, tu a eu raison.

[100] actual Game sequence - Inferior?  

tderz: Black lives with 2+2 = 4 points (2x W1 + 2x white+circle),
hence 1 point less than in diagram [30] above (as p won't be a point).
The 5 black+circle are worth 10 points.
The net result is thus
Maximum Territory for Black minus Black's territory loss minus loss by black+circle =
10 - 10 - (10-4) = 10 - 10 - 6 ... (ähem mathematics) ,
but Black's loss is now 16 points (in Gote for White).
White catches 1 black+circle (=2points) more, loses 1 point at W1 and p is only a dame point (=> 2-1+1 = 2).

After correction by Bill

This is indeed 1 point inferior than the 16 points in diagrams[30]-[33] above as pointed out by Bill.
As both variations end in White's gote, they are directly comparable.

Before correction by Bill

      • This is 2 points better than the 13 points in dia.[30] ***above.
        As both variations end in White's gote, they are ***directly comparable.

[110] result actual Game sequence  

tderz: This is why I consider this the best solution.
White could not hamper Black's life,
yet Black cannot avoid the capture of 5 black+circle (instead of lower 4 black+circle).

[120] Black's failures to live - snapback  

tderz: these were sequences (equiv. to dia.[60])which I 'saw' during the game.

[130] Black's failures to live - damezumari  

tderz: Black's damezumari, Black a - White b has to follow.

[140] Black can live - in Gote  

tderz: Black can live - in Gote with the sequence a-b-c (c...a-b, if White was expecting ko fights and needed threats; here not the case).
Black even has forced White to accept the capture of only 4 black+circle.
Due to tedomari the Sente/Gote-difference
might be worth only zero to 1/2 point at this stage of the [ext] game .
White cannot play W3 = a herself due to damezumari.

[1] Bill: "the net result seems to be 6+11 = 17 points, which White snatched away (in Gote)."

Again, let me point out once more the potential for confusion when using deiri counting. Black can make x points with gote, or White can make y points with gote. It is misleading to say that whoever made the play snatched away x + y points. That implies that the position was worth the same as if the other player had made a gote play. Of course, it is natural to think that a gote that is worth x + y points gains x + y points, but that is not so with deiri counting. It is so with miai counting, however. If you want to talk about gain and loss, use miai counting.

tderz Bill, once in a year I read about miai and deiri counting, usually when browsing (again) through Charles Matthews' 'Ko'-book. Then I understand it, but soon afterwards I seem to forget the terminology.

TsumegoFromGames70/attempts last edited by tderz on November 24, 2006 - 10:18
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