Life In 19x19 :: Game Against Cosumi

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Game Against Cosumi http://www.lifein19x19.com/viewtopic.php?f=4&t=14349	Page 1 of 1

Author:

WindCaliber [ Sun Jul 02, 2017 8:14 pm ]

Post subject:

Game Against Cosumi

Hi everyone,

I'm new to the forums, but have been playing Go intermittently for quite a few years now. I was wondering if anyone could offer any commentary on this game I just played with Cosumi. I never really knew my rank as I don't play on any online servers; looking at a screen always seemed to make it harder for me, and with college taking up all my time, I would say I only played a few games for the past couple of years.
Personally, I've always said my rank was 7K, just as a ballpark estimate from when I used to play IgoWin, doing Go problems, and an elderly Taiwanese man at the club at my college made some offhand remarks that I may have been even 3K(which made me excited). Even though I hardly played games, I would say that I followed Go alot, pretty much looked at all the commentaries by An Younggil, watched a lot of Lee Hajin's videos, and recently watching Nick Sibicky's online lectures and reviews.
I find that some of my weaknesses are making overly safe moves, always thinking I'm "behind", not knowing how to invade or properly reduce, which usually results in the opponent converting a large moyo into territory, and I think I'm weak at joseki.

Anyway, long story aside, I was wondering if anybody could maybe estimate my rank based on the moves I play.
Any help is appreciated

Attachments:

170702 - VsCosumiWin (White) 2.sgf [1.28 KiB]
Downloaded 768 times

Author:	EdLee [ Sun Jul 02, 2017 9:37 pm ]
Post subject:
Hi WindCaliber, Welcome. R8 is not small. C17 big. S18. P17 not small. Running is strange. (e.g. P17 much bigger.) Why ? Why ? You're happy to take H4.

Author:	WindCaliber [ Mon Jul 03, 2017 2:33 pm ]
Post subject:	Re:
Thanks for the helpful tips! Here are my thoughts during the game and some questions. If there's anything else, please let me know I think I have trouble judging whether a move like that is small or not. My thought was that I may have been out of immediate danger, but I do see that being in such a cramped space is not so good. I should've seen C17! Is the reasoning that at P18 and creating a wall facing left would be bad for white? If so, I can see how S18 would prevent that! Is the reasoning that if at P18, then white's top would be very small? Is this the same meaning? My reasoning was that I wanted to reduce the bottom and prevent the connection of the middle group, but since you point it out, it does look a bit too cautious. Maybe something a bit more active towards the center or pushing down farther would be better? Good point, I totally missed that! I think I was too concerned with cutting the stone off. If hane at H4, the result would be better for black than in the game? EdLee wrote: Hi WindCaliber, Welcome. R8 is not small. C17 big. S18. P17 not small. Running is strange. (e.g. P17 much bigger.) Why ? Why ? You're happy to take H4.

Author:	Tapani [ Mon Jul 03, 2017 9:57 pm ]
Post subject:	Re: Game Against Cosumi
First, being 9-10k IGS so I am probably more clueless than the OP. Even if a elderly Taiwanese man also said that I was maybe 3k ... (I suspect Taiwan ranks are a bit inflated due to the huge number of tournaments). About EdLee suggest R8 for white. This move would not be on my radar at all! There is a whole board of bigger moves available? Wouldn't black respond with Q9 (or even Q7 or P6)? This would keep white low, build influence and strengthening his lonely stone (which is weaker than the white group it is attaching to)? After this if black gets in something like P6, he might be making decent profit? in the bottom half/center?

Author:	EdLee [ Tue Jul 04, 2017 1:42 am ]
Post subject:
Hi WindCaliber, B is happy to block at R8, but B missed it. S18 connects W with o17.

Author:

Schachus [ Tue Jul 04, 2017 6:13 am ]

Post subject:

Re: Game Against Cosumi

Hi tapani, I think this is an important question, that might help you get stronger!
I see two points, why r8 should be basic instinct for both players(at my level, which is 2k-3k):

1. Contact moves make the lokal situation usually urgent. White played a diagonal attatchment for 14, b should "want" to reply(of course unless there is something very big elsewhere)

2. The white group has not got 2 clear eyes yes. At 14, w said "I'm going to adress this by living locally"(jumping out would be the other(maybe better option)), for which he was looking for eyespace. B should now force w to really do that(live in gote), by blocking at r8(of course, w can still jump out, but exchanging r7 for r8 has then no sense and strengthens b's q7 stone). In general, if your oponents have to live with their groups, you should be happy to exchange your outside moves with them living inside.

I put some variations, (not sure whether they are that great) to illustrate this point.

Edit: Just to add, actually joseki would be for w to jump out even before attaching at 3-3, but generally to jump out and (depending on b's reaction) attack q7 instead of strenthening it with 14

Attachments:

blockatr8.sgf [2.59 KiB]
Downloaded 739 times

Author:	WindCaliber [ Tue Jul 04, 2017 3:08 pm ]
Post subject:	Re:
Yes, that's what I meant EdLee wrote: Hi WindCaliber, B is happy to block at R8, but B missed it. S18 connects W with o17. Thanks for the suggestions and variations Schachus! If black extends at q10, should white respond or tenuki? Also, are you sure about jumping out after the one space high approach? I did a little bit of studying the Kobayashi and it seems that white attaching on the other side of black is more common, although that seems complicated(at least to me).

Author:	Tapani [ Thu Jul 06, 2017 5:51 am ]
Post subject:	Re: Game Against Cosumi
Thanks Schachus! The concept of a part of the board becoming uninteresting is a bit difficult at first to me. But overall I think I get your point with the lines you show.

Author:	Schachus [ Sat Jul 08, 2017 4:56 am ]
Post subject:	Re: Game Against Cosumi
Tapani wrote: Thanks Schachus! The concept of a part of the board becoming uninteresting is a bit difficult at first to me. But overall I think I get your point with the lines you show. Well take for example the position in which I wrote that. I'm not claiming that my judgement of this is totally correct, but I think it will help your play to think about, which areas of the board allow for bigger territorial swing: Click Here To Show Diagram Code [go]$$W $$ +---------------------------------------+ $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . T . . . . . \| $$ \| . . . O . . . . . , . . . . . X . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . T . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . , . . . . . , . . . . . , . . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ \| . . . . . . . . . . . . . . . X O . . \| $$ \| . . . . . C . . . . . . . . . . O . . \| $$ \| . . O . . . . . . . . . . . X . . . . \| $$ \| . . . . . C . . . . . . . . . O . . . \| $$ \| . . . O . . . . . X . . . X . , O . . \| $$ \| . . . . . X . . . . . . . . . X O . . \| $$ \| . . . . . . . . . . . . . . X . X . . \| $$ \| . . . . . . . . . . . . . . . . . . . \| $$ +---------------------------------------+[/go] On the right side, there is already a white group, ehich is rather low(3rd line) and reasonably safe. This means if black wants to surrond territory on the right side, he is not going to surround much(the bottom of the right is already taken) and his moves will not strongly attack white.Hence surrounding territory would be the single purpose, which is not interesting enough(note that this is entirely different as long as the white group is usafe, because then black might surround this efficently while threatening white). White on the other hand, can surround territory on the right if he wants, but its not so much extra, as he already has points there, and its not going to be a large framework, because he is low. Compared to that, the top side is almost empty, so a single move there can do a lot to the expected territorial balance. This is what I think about, when I decide, from which of the triangled points I want to approach a hoshi stone. In this case, I want the top, because a black answer on the right doesnt seem to give him much. Another area that seems interesting to me is the bottom. This is because, black has build kind of a wall(high not low) and with extra moves around the circled he might build a large box, that could potentially increase his territory a lot. On the other hand this is harder to judge in size, because such a framework would still be invadeable and the "wall" has quite some holes.

Author: Bill Spight [ Sun Jul 09, 2017 7:33 pm ]

Post subject: Re: Game Against Cosumi

Click Here To Show Diagram Code: [go]$$Wcm16 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X 1 . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O . . . | $$ | . . . O . . . . . X . . . X . , O . . | $$ | . . . . . X . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . X . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Ed Lee suggested :w16:

. Here is one way to see that it is a good play.

Click Here To Show Diagram Code: [go]$$Wcm8 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 8 7 . . | $$ | . . . . . . . . . . . . . . . . 9 . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 1 . . . | $$ | . . . O . . . . . X . . . 2 . , 5 . . | $$ | . . . . . X . . . . . . . . . X 3 . . | $$ | . . . . . . . . . . . . . . 6 . 4 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Suppose that the game had gone this way, with Black replying at :b9:

instead of the pincer (probably not best play). Through :w14:

is joseki. Then the attachment, :b15:

, is unusual. :w16:

is solid. Maybe a little slow, but you can't say that it is a bad play.

Click Here To Show Diagram Code: [go]$$Wcm16 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . 1 . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X 2 . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O . . . | $$ | . . . O . . . . . X . . . X . , O . . | $$ | . . . . . X . . . . . . . . . X O . . | $$ | . . . . . . . . . . . . . . X . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

By contrast, if Black gets :b17:

in he is building strength on the right side, preventing White from making the normal extension in the bottom right, and putting pressure on the White group there. This position is not good for White.

Click Here To Show Diagram Code: [go]$$Wcm14 $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X 2 . . | $$ | . . . . . . . . . . . . . . . . 1 . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . O . . . | $$ | . . . O . . . . . X . . . . . , O . . | $$ | . . . . . X . . . . . . . . . X W . . | $$ | . . . . . . . . . . . . . . X . X . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

All of which means that Black should have played :b15:

in response to :w14:

. Which, in turn, means that White should not have played :w14:

. And if you are not going to make a base with :w14:

, why play the attachment at :wc:

earlier? (Not that pros have not played the :wc:

attachment. But then they followed up with more sophisticated play.

)

When I was learning go the textbooks said not to extend from a corner (except one with a 4-4 stone) without making an enclosure first. But even at that time, the idea was being revived — such extensions had been played in earlier centuries.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . 9 . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . d c b . 8 . . . | $$ | . . . O . . . . . X e . . . . , . . . | $$ | . . . . . X . . . . . . . . a X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

The high approach, :w8:

, was supposed to be the refutation. But it turns out that after the pincer, :b9:

, this is not such an easy position for White. :w8:

is outnumbered locally and it has no base. Furthermore, as we have seen, making a base is problematical.

In this kind of situation White generally wants to play lightly, to reduce Black's framework, possibly sacrificing a stone or two — or more.

Moves which have been tried include "a", which usually leads to complicated fighting, and the jumps, "b", "c", and "d". "d" is quite light.

With the advent of AlphaGo, perhaps we will see "e", as well.

N. B.: White can also play elsewhere, such as approaching the top right corner. With so many choices on the bottom side, it is often a good idea to play elsewhere and see how the game develops. An opening pincer is not sente.

Click Here To Show Diagram Code: [go]$$Bc $$ +---------------------------------------+ $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . , . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . a 8 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . . . . X . . . . . , . . . | $$ | . . . . . X . . . . . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

White may also approach at :w8:

or "a", which are easier for White to handle.

Black does not have a severe pincer.

Author:	EdLee [ Sun Jul 09, 2017 7:53 pm ]
Post subject:
Quote: And if you are not going to make a base with , why play the attachment at earlier? (Not that pros have not played the attachment. But then they followed up with more sophisticated play. ) Hi Bill, Quick search on pro database: the attachment of at 3-3 is not zero, but indeed quite rare (60+ cases), compared to the most popular move for the local shape (1650+ cases). ( No AlphaGo input, though. )

Author:	Rémi [ Mon Jul 17, 2017 6:59 am ]
Post subject:	Re: Game Against Cosumi
Analysis by Crazy Sensei. Black missed an interesting cut at move 102: https://www.crazy-sensei.com/?lang=en&l ... 1&move=102

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