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 Post subject: Can harakiri be successful?
Post #1 Posted: Fri May 22, 2020 10:39 am 
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I have an absolute beginner's question at the end of a game. I've known the rules for a month now. I mostly play against the program "Many Faces of Go". At the moment with 1 hour time to think on the 19x19 board and against the 15 kyu level.
What I still find very difficult is counting, and in the following game I found out that I had a bit more points before my 179th move. Now I would like to know, how an "incorrect" game really affects me. So, I went on and collected my opponent's stones, but I also put my stones fot this in my position and made a minus, so that I was a few points behind on my 197th move. So far so clear.
Now I'm thinking about the following Question for quite a while: If your opponent has a large empty area at the end, and you invade it with your own stones, they won't survive, but to kill them, the opponent has to put his own stones into his area, and maybe he will loose some points this way?!!? I have already lost, so I have practically nothing left to lose, and if the opponent needs a few stones too many to kill mine, I might be able to score some points plus?!!? The computer scored the same in my test game. In the end I was ahead, even though my hara-kiri strategy was quite nonsensical and actually unsportsmanlike. How does it behave now exactly??
The analyses were made with Leela Zero at Sabaki.
I attached the game as a .sgf file to this thread.
Thanks a lot!!!


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Harakiri-Test.sgf [4.4 KiB]
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 Post subject: Re: Can harakiri be successful?
Post #2 Posted: Fri May 22, 2020 10:53 am 
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If you try to invade an area that is already completely enclosed, and your opponent responds to every move, then the invasion doesn't cost anything. Each black stone gives a point to your opponent, but your opponent plays in his territory which loses one point, so the net result is zero.

Other remarks: you made many useless moves, like :b59:, :b85:, moves 101, 123, 129, 157, 179, 181, 183, 187, 189, 191.

Maybe you don't understand the rules correctly. Stones that won't be able to live after a sequence of alternating plays are considered as "dead". You don't have to remove them from the board. For instance

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


Black has 5 points here: 4 points of territory + 1 prisoner.

Black doesn't need to capture the white stone. If nevertheless Black chooses to do so,

Click Here To Show Diagram Code
[go]$$B
$$ +----------
$$ | X X . X .
$$ | . X . X .
$$ | X X X X .
$$ | . . . , .[/go]


then Black ends up with 4 points (3 points of territory + 1 prisoner). So the capture actually loses a point.


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 Post subject: Re: Can harakiri be successful?
Post #3 Posted: Fri May 22, 2020 11:26 am 
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Thanks for the hints, especially with regard to the pointless moves. I'll take a close look at it, and try to learn. The rules, however, I think I have already understood, but there are just two problems:
1. because of Corona, for example, I can visit no go club and cannot play face to face with people. I know the rules only since 3 weeks, so I have never played against an experienced person, and
2. If the areas in which the stones are trapped are larger and not as defined as in your example, then I am still not clear whether they are always trapped due to uncertainty.

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Post #4 Posted: Fri May 22, 2020 11:58 am 
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jumapari wrote:
Thanks for the hints, especially with regard to the pointless moves. I'll take a close look at it, and try to learn. The rules, however, I think I have already understood, but there are just two problems:
1. because of Corona, for example, I can visit no go club and cannot play face to face with people. I know the rules only since 3 weeks, so I have never played against an experienced person, and
2. If the areas in which the stones are trapped are larger and not as defined as in your example, then I am still not clear whether they are always trapped due to uncertainty.


Your question is a reasonable one, and one that has been asked several times here, and answered. Sorry, I don't know exactly where these discussions are or exactly what to search for. The rule is that dead stones are removed from the board at the end of the game without having to capture them. The question then arises, what stones are dead? This is surprisingly difficult to answer. The latest version of the Japanese professional rules gives a definition that is, at best, ambiguous. But in practice, the problem has arisen with good play only a few times in the long history of go.

Fortunately for you, there is a practical way to answer the question. Play the game out until all dead stones have been captured, or you both agree that they are dead. But, instead of using Japanese style rules, use area scoring, which counts both stones and territory on the board. The difference in the final score is rarely more than one point, and it is easy to switch between the two rules. There is even a way, thanks to yours truly and others, to play by area scoring but count the score at the end a la territory scoring. :) This is part of the rules of the American Go Association (AGA), at https://www.usgo.org , :)

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 Post subject: Re: Can harakiri be successful?
Post #5 Posted: Fri May 22, 2020 12:18 pm 
Honinbo

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A couple of comments. :)

Go to move 177.


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 Post subject: Re: Can harakiri be successful?
Post #6 Posted: Fri May 22, 2020 12:50 pm 
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Let me add a few details then.

:b59: is useless because the two white stones are in atari and can't escape. If White wants to escape, then White would need to play at K12, but then you would respond with J12.

:b85: is useless for the same reason. If White O15 then Black N15.

Move 101 is unnecessary because all your stones are connected. For instance, M11 and N10 are connected because if White plays M10 then you can play N11 and vice-versa. M11 and L10 are connected because if White plays L11 you can capture. Maybe you wanted to make an eye, but that's unncessary because you already have an eye at F11, and in case of emergency you can connect to the second eye O16. Or you can connect to the bottom right corner, as you did later at move 103.

123 is useless for the same reason as 59 and 85.

Now, look at the position at move 128. The 9 stones around P12 are dead. Try to convince yourself about that: if White makes a move to try to make an eye, Black can find a move that prevents it.

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Post #7 Posted: Fri May 22, 2020 4:28 pm 
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This might be a little bit advanced but situations arise where Black has surrounded some White stones and the White stones can't make eyes but Black has to take the surrounded stones off, possibly playing moves that White doesn't answer. This happens because part of the Black surrounding stones could be captured if the White stones aren't taken off. Actually capturing the White stones then costs Black some points.

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 Post subject: Re: Can harakiri be successful?
Post #8 Posted: Sat May 23, 2020 7:36 am 
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And continuing from the last, you need to check liberties carefully in that situation, because if you can remove outside liberties while there are still two or more inside liberties between your dead stones and this part of the surrounding group your dead stones are not dead (they are alive in seki)

Also, dead stones are dead if they cannot form a live group IF the opponent responds. That means that each such play that threatens to make a live group is a ko threat that costs you nothing.

That makes it important to learn to see "this group of my stones is dead" (as long as the opponent responds) as early as possible and not waste these ko threats by playing on there. Except, of course, if a play inside can mean part of the surrounding group is cut off.

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Post #9 Posted: Sat May 23, 2020 7:50 am 
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Also, if you are using a tool like MFOG to learn from....

Set it to use the "randomize" option and set it strong enough that you need to take 3-4 handicap stones to have much of chance of winning. When you begin winning more than half the time, drop a handicap stone. If down to two stones, set MFOG up 3 kyu and back to four stones.

That way, MFOG will not be making the mistakes typical of your level and will be able to punish those that you make so you learn not to make them.

Take advantage of other features besides its ability to play. The "go problems" for example. MFOG will feed you a set of problems. It will remember which you get wrong and which right. The ones you get wrong remain in the set until you learn to do them right and the ones you keep getting right will be replaced by new problems.

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