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 Post subject: Handling invasions
Post #1 Posted: Sat Oct 01, 2016 12:11 pm 
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Not sure what subforum is the right place for this. Are DDKs beginners or amateurs?

Anyway, I seem to lose many games on Tygem when my opponents do outrageous invasions. My gut feeling is that many of these are not very sound, but I often end on the losing side of this. Also stopping "toothpaste" (snaky long groups) seems quite hard sometimes.

Example - how should I handled the invasion below? It is a quick game, so any but superficial reading was not really possible.

I am black, and white's first move is the invasion.


Only the 10 first moves or so are relevant, the rest is there just demonstrate the disaster for black that followed...

This is not the only such game. There are dozens of others with the same pattern.


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 Post subject: Re: Handling invasions
Post #2 Posted: Sat Oct 01, 2016 3:40 pm 
Oza

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:w24: is the problem. Should be at N18.

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Last edited by DrStraw on Sun Oct 02, 2016 5:07 am, edited 1 time in total.
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 Post subject: Re: Handling invasions
Post #3 Posted: Sat Oct 01, 2016 4:26 pm 
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Hi Tapani,
I'm not a very good player myself, but here are my 2 cents.

Your first move H14 doesn't look very good to me because it aims at enclosing White with a cap, however, the marked intersection, J15, is a weak point through which White can escape. The one point diagonal jump is called the "elephant's step" and it is a weak shape. J15 is called the "elephant's eye" and is the key for white to tear apart the two Black stones.

Defending in H17 looks easier. I show two possible variations. In the two first ones, after White G14, A, B or C (threatening White's group) are possible continuations.



Later in the game, White 23 is the "monkey jump". You must learn by heart the sequence that allows to stop it. The one I show works for a jump under the M17 stone (the most common case). Two other sequences must be used for a jump under a lone stone in N17 or under a lone stone in L17 (the most difficult case).

Once the damage is done, it seems to me that you try to prevent White from getting out at all costs.

Always think in a global context : the most important is not to save the most possible points. The most important is to live : defend your weak groups.
After White 25, your L18 stones are in danger of being killed. It is urgent to connect them with O14, for example. See variation.

Then, the White stones in the center are weak, but your upper left black group is weak too. Normally, you should look for a move that would attack your opponent and defend yourself at the same time.
There doesn't seem to be any here, so I show moves that just take care of Black's group, making two eyes. White must run. Let her do. The game is not finished yet, and you still have a great potential on the right side.

At the end of the variation, I show some possibilities for White.
A closes the moyo.
B is a big move in the bottom edge.
C (the "shoulder hit") aims at destroying Black's moyo.


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 Post subject: Re: Handling invasions
Post #4 Posted: Sat Oct 01, 2016 8:05 pm 
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DrStraw wrote:
:w24: is the problem. Should be at N19.


There's a stone on N19 already, so I wanted to double check that. After reviewing it, I think DrStraw meant N18. This move stops W from connecting on the first line.

I feel that your play against this invasion shows good promise. I think you were able to:
1) paying attention to shapes
2) follow an overall strategy of trying to capture a whole or part of the invading group.
3) You keep trying new things.

There are two things working against your strategy here.
A) W has strength to the right of the invading stone. He can threaten your stones, connect to it. This limits your options, or you might need to play more carefully which gives more chances for W to escape.
Example: 6 at L13
Example 2: 8 at L16
B) For now, you may not be able to read far enough ahead to see that the invading stones will or will not be captured.

It's tough but possible (and fun) to train the above mentioned "B". In many cases, if you can't read it out to the end, it's fine to just play simple sequences you can read out (like Pio2001 suggested below; defending at H17). Sometimes sequences go on forever and it's not possible to read everything out; on a fun online game, I might try it out anyway, but in a tournament I would stick only to moves and sequences I am confident will work.

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 Post subject: Re: Handling invasions
Post #5 Posted: Sat Oct 01, 2016 8:50 pm 
Judan

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I think you're on the right track, and just need more practice. If you get invaded a lot on Tygem and invasions are giving you difficulties... keep playing on Tygem and getting invaded. You'll see what didn't work, and keep improving.

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 Post subject: Re: Handling invasions
Post #6 Posted: Sat Oct 01, 2016 9:03 pm 
Judan

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Kirby wrote:
I think you're on the right track, and just need more practice. If you get invaded a lot on Tygem and invasions are giving you difficulties... keep playing on Tygem and getting invaded. You'll see what didn't work, and keep improving.


Let me second that, and add that through :b52: you actually came out pretty well. White has two weak groups ripe for attacking, and Black has built strength in the center facing the right side. :) Don't be so pessimistic.

More mannana.

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 Post subject: Re: Handling invasions
Post #7 Posted: Sun Oct 02, 2016 3:53 am 
Tengen

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Tapani wrote:
Anyway, I seem to lose many games on Tygem when my opponents do outrageous invasions. My gut feeling is that many of these are not very sound, but I often end on the losing side of this.

Whilst Tygem players do make many outrageous invasions, I don't think this is one of them. If you are overly dismissive of your opponent's moves it is easy to make mistakes yourself, get angry/frustrated and get bad results. An important point in this position is that black does have some weaknesses, notably that g16 is a peep against f16 (the white stone at d17 helps white here) so the usual shape moves of connecting a 3 space low-to-high extension of h17 or h15 have some problems. So my initial feeling of this position would be that black should be able to connect his groups (ensuring his safety, so this is not a splitting and attacking invasion) but white should be able to save his stone and reduce black. With that 'base result' I would then actually do some reading to see how I could get that, and then look for better results, such as killing white. For the latter the kosumi at j15 would be my initial move.

As a more general point (and not applicable to this invasion), I would find Tygem players would often invade some potential territory between 2 already settled positions much too early. In such cases it is often a good idea (plus it is funny and probably annoys them) to simply tenuki and play some bigger move elsewhere on the board. If they jump out you just play some other big move, secure some territory etc. If they make another invasion weak group then maybe rather than covering the invasion (and they make some tiny life inside) you could drive them out and create a splitting attack.

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 Post subject: Re: Handling invasions
Post #8 Posted: Sun Oct 02, 2016 5:45 am 
Gosei
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You still have to practice judging the position. At the end of your sequence, suppose that White cuts at 1 below. Black should atari with 2 and then kill everything on the top with 4 through 8. Who is laughing now? :rambo:

Note that even if White's upper right corner did not die, Black 4 threatens to throw in and start a ko at M19. White had not completely connected to the top in the game. You were too trusting!
Click Here To Show Diagram Code
[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . O . O . 7 . 8 . . |
$$ | . . . . . . . X . O X . 4 5 6 O O X . |
$$ | . . . O . X . . . O X X . O . O X . . |
$$ | . . . O . X O O O , O X . . O X . X . |
$$ | . . . . . X . . O O X X . . O X . . . |
$$ | . . O X . . . X . X O X . X . X . . . |
$$ | . . O . . . . . . X O . X O . . . . . |
$$ | . . . . . . . . . . O O O X X . . . . |
$$ | . . . . . . X X X O O X X O . . . . . |
$$ | . . . , . . . O O O X . X . . , . . . |
$$ | . . . . . . . O X O O X . . . . . . . |
$$ | . . . . . . . . . X X 1 2 . . . . . . |
$$ | . . . . . . . . . . . 3 . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . O . . . . . , X . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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 Post subject: Re: Handling invasions
Post #9 Posted: Sun Oct 02, 2016 3:52 pm 
Dies in gote

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Wow! Never expected this many responses.
Thank you all, it is a little overwhelming but in a good way :-)


DrStraw:

never even considered N18. The only thing that went through my head there
was "monkey jump. it is connected. better play L18 so it at least
cannot create eyes or a point of territory"

Still not sure how my thought process could have arrived at me playing L18..


pio2001:

thank you for detailed the analysis of lines.

Did not even consider going beneath his invading stone actually.
Maybe I somehow felt the area was mine already. :-)
Just debated whether to cap or shoulder hit the stone.

Regarding monkey jumps. While I have seen and used them, I really have
no standard way to deal with them - let alone
different plays depending on what stones are on the board.
Thank you for mentioning them!
Question: in your sequence, how about :w27: @ O18 instead of L18?


Bill:

thanks. Last nights pessimism was more caused by a few losses in a row before posting ..
(yes, I lost this game as well)


Kirby:

words of wisdom indeed. Playing more, getting invaded more is what I intend :-)
AND .. to try those invasions myself and see how others deal with them :D


Uberdude:

Thank you, and I did consider J15, but for some reason decided against it. Maybe because
it felt like H14 kept my stones more easily connected.

Why I feel his stone is overplaying is maybe because of a rule of thumb I saw in a youtube go lecture (Nick):
* one [stone] against one [enemy stone] - can tenuki
* one against two - must continue
* one against three - must tenuki

and here my opponent goes with one stone against 5-6 stones!



ez4u:
wow! nice! almost magic to me :-)

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 Post subject: Re: Handling invasions
Post #10 Posted: Mon Oct 03, 2016 2:20 pm 
Lives with ko

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Tapani wrote:
Question: in your sequence, how about :w27: @ O18 instead of L18?


Then Black N19 atari, and White can't get out. She must capture and Black cuts.
That's why this sequence only works if there is a Black stone in M17.

Here are some standard sequences to stop monkey jumps. If you are the one jumping, don't try to punish at all costs if your opponent stops differently. You may get one or two more points, but most of the times you loose the sente. The sequences shown here are all sente. This is an important feature of the monkey jump.

In the third case, the optimal move is the tobi, but the jump is a trick move. It is difficult to stop properly.



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 Post subject: Re: Handling invasions
Post #11 Posted: Tue Oct 04, 2016 9:33 am 
Dies in gote

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Thank you pio2001!

Really appreciate the monkey jump josekis!

After your last post I went and wondered a little -- where would I get my hands on good josekis against monkey jumps. Thanks!

In general, what are good sources for josekis for handling standard situations like:
- splitting 3-point extension (both sides)
- splitting 2-point extension (should not be possible, but people do try and succeed against me)
- other common situations in ddk games :-) [ I understand many situations never see the light of day in pro games since the pros both know the outcome - and never play them out ]

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 Post subject: Re: Handling invasions
Post #12 Posted: Tue Oct 04, 2016 1:18 pm 
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In Learn to Play Go vol 2, Janice Kim and Jeong Soo-hyun give the following example.



But if your 2 points extension is attacked by an opponent keima in P8, that is another story. You must protect with a tobi in P9 before your opponent makes a keima.

Some of these sequences are shown in Fan Hui's book "L'Âme du Go" (in french).


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