It is currently Wed Apr 26, 2017 10:47 am

 All times are UTC - 8 hours [ DST ]

 Page 1 of 1 [ 7 posts ]
 Print view Previous topic | Next topic
Author Message
 Post subject: Counting question #1 Posted: Wed Feb 22, 2017 7:53 am
 Beginner

Posts: 6
Liked others: 3
Was liked: 2
Hi! This is a very, very simple counting question. But bear with me - I'm just a beginner.

The question is: "What is the value of playing at B1". I get 3+4 = 7 points. The "book" says 8 (no explanation). What did I miss?

Top

 Post subject: Re: Counting question #2 Posted: Wed Feb 22, 2017 7:57 am
 Dies with sente

Posts: 81
Liked others: 3
Was liked: 17
Rank: KGS 2k
KGS: Schachus12
If black gets it, white a3 is not going to be a point, he will have to connect there later. That is the point you forgot to count.

Edit: actually, in this case, I think the move is even bigger, beacause after white b1, a later play at d1 is sente for white, so we cannot count the exchange black d1 white c1 as sente for black.
Edit2, ah I see, you also didnt count in the fact, that after black gets b1, he will later have to take the white stone out. So I now count 9 points, your 7 +1 the one above, plus 2 more for white d1 in sente -1 for that. It seems it's not that simple;)

Top

 Post subject: Re: Counting question #3 Posted: Wed Feb 22, 2017 8:09 am
 Beginner

Posts: 6
Liked others: 3
Was liked: 2
Wow, that was fast!

> If black gets it, white a3 is not going to be a point,
> he will have to connect there later. That is the point
> you forgot to count.

I was thinking about that. But if black plays at B1 first he can't play A1 because of the white stone at C2. He would first have to capture that stone, reducing his territory by 1. Only then white would have to defend at A3. So the count wouldn't change.

Did I get that right?

Top

 Post subject: Re: Counting question #4 Posted: Wed Feb 22, 2017 8:13 am
 Dies with sente

Posts: 81
Liked others: 3
Was liked: 17
Rank: KGS 2k
KGS: Schachus12
Baywa wrote:
Wow, that was fast!

> If black gets it, white a3 is not going to be a point,
> he will have to connect there later. That is the point
> you forgot to count.

I was thinking about that. But if black plays at B1 first he can't play A1 because of the white stone at C2. He would first have to capture that stone, reducing his territory by 1. Only then white would have to defend at A3. So the count wouldn't change.

Did I get that right?

Yes that seems right(what I only noticed by edit 2). I at the moment do not count the move to be 8 points(but rather 9), so maybe if 8 is right, someone should explain it to the both of us:)

Top

 Post subject: Re: Counting question #5 Posted: Wed Feb 22, 2017 8:34 am
 Oza

Posts: 3881
Location: Cambridge, UK
Liked others: 133
Was liked: 1887
Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
If black plays first, we will eventually end up with:
`[go]\$\$Bc\$\$ ------------------- \$\$ | . . . . . . . . . |\$\$ | . . . . . . . . . |\$\$ | . . , O . . , . . |\$\$ | . . . O X . . . . |\$\$ | . O . O X . . . . |\$\$ | . . O O X . . . . |\$\$ | O O X X . X , . . |\$\$ | O X . X . . . . . |\$\$ | O X X . . . . . . |\$\$ -------------------[/go]`

If white, then:
`[go]\$\$Wc\$\$ ------------------- \$\$ | . . . . . . . . . |\$\$ | . . . . . . . . . |\$\$ | . . , O . . , . . |\$\$ | . . . O X . . . . |\$\$ | . O . O X . . . . |\$\$ | . . O O X . . . . |\$\$ | . O X X . X , . . |\$\$ | O . O X 2 . . . . |\$\$ | . O 5 1 4 . . . . |\$\$ -------------------[/go]`

Note that when counting a gote move like this you give each player their expected sente follow-ups, so white could get 1 for 2 above, and then later black 4 for 5 (there's actually a tiny chance that white could play at 4 but that's gote, whereas black's 4 is sente to capture 1 stone and more in ko so it should be his sente move later in the game).

So now you can count the difference between these 2 positions.

The way I would actually do this in my head is (knowing those terminal positions) look what intersections become points for black if he gets it (triangles) and what become points for white (squares). Remember captured stones count for 2 so there's a difference of 9 here.
`[go]\$\$Bc\$\$ ------------------- \$\$ | . . . . . . . . . |\$\$ | . . . . . . . . . |\$\$ | . . , O . . , . . |\$\$ | . . . O X . . . . |\$\$ | . O . O X . . . . |\$\$ | . . O O X . . . . |\$\$ | S O X X . X , . . |\$\$ | O # Q X T . . . . |\$\$ | S . . T T . . . . |\$\$ -------------------[/go]`

Top

 Post subject: Re: Counting question #6 Posted: Wed Feb 22, 2017 9:18 am
 Beginner

Posts: 6
Liked others: 3
Was liked: 2
Thanks a lot for that detailed response, Uberdude! My counting based on the exchange Wb1 (captures), Bd1, Wc1. Bd1 doesn't seem to be worth much but if W ignores, then Bc1 and W has to connect at b2, loosing one point. But it all depends on what other endgame moves there are, doesn't it?

BTW: This problem is from the online course on 321go.org, Chapter 5.7.2.

Top

 Post subject: Re: Counting question #7 Posted: Wed Feb 22, 2017 10:12 am
 Judan

Posts: 6027
Liked others: 1404
Was liked: 2315
I prepared an SGF file, but Uberdude beat me to it.

Just a couple of small points.

`[go]\$\$Bc Black first\$\$ ------------------- \$\$ | . . . . . . . . . |\$\$ | . . . . . . . . . |\$\$ | . . , O . . , . . |\$\$ | . . . O X . . . . |\$\$ | . O . O X . . . . |\$\$ | . . O O X . . . . |\$\$ | W O X X . X , . . |\$\$ | O X O X b . . . . |\$\$ | x 1 B b b . . . . |\$\$ -------------------[/go]`

After and are later protective plays. x is a dame.

Local result for Black: +5

`[go]\$\$Wc White first\$\$ ------------------- \$\$ | . . . . . . . . . |\$\$ | . . . . . . . . . |\$\$ | . . , O . . , . . |\$\$ | . . . O X . . . . |\$\$ | . O . O X . . . . |\$\$ | . . O O X . . . . |\$\$ | w O X X . X , . . |\$\$ | O X O X 4 . . . . |\$\$ | w 1 7 3 6 . . . . |\$\$ -------------------[/go]`

After is later sente. Black normally replies with Later, is sente.

Local result for Black: -4

Swing = 9

Initial local value for Black: 0.5

Each gote play gains 4.5.

`[go]\$\$Wc Black komaster\$\$ ------------------- \$\$ | . . . . . . . . . |\$\$ | . . . . . . . . . |\$\$ | . . , O . . , . . |\$\$ | . . . O X . . . . |\$\$ | . O . O X . . . . |\$\$ | . . O O X . . . . |\$\$ | . O X X . X , . . |\$\$ | O . O X 6 . . . . |\$\$ | . O 5 3 4 . . . . |\$\$ -------------------[/go]`

If Black is komaster she can play . The result is the same as the main line.

`[go]\$\$Wc White komaster\$\$ ------------------- \$\$ | . . . . . . . . . |\$\$ | . . . . . . . . . |\$\$ | . . , O . . , . . |\$\$ | . . . O X . . . . |\$\$ | . O . O X . . . . |\$\$ | . . O O X . . . . |\$\$ | . O X X . X , . . |\$\$ | O . O X 5 . . . . |\$\$ | . O 6 3 4 7 . . . |\$\$ -------------------[/go]`

If White is komaster - is very bad for Black.

_________________
"Drooling Banjos"

Top

 Display posts from previous: All posts1 day7 days2 weeks1 month3 months6 months1 year Sort by AuthorPost timeSubject AscendingDescending
 Page 1 of 1 [ 7 posts ]

 All times are UTC - 8 hours [ DST ]

#### Who is online

Users browsing this forum: No registered users and 1 guest

 You cannot post new topics in this forumYou cannot reply to topics in this forumYou cannot edit your posts in this forumYou cannot delete your posts in this forumYou cannot post attachments in this forum

Search for:
 Jump to:  Select a forum ------------------ Life In 19x19.com General Topics    Introductions and Guidelines    Off Topic    Announcements    General Go Chat    Beginners    Amateurs    Professionals       Lee Sedol vs Gu Li    Go Rules    Forum/Site Suggestions and Bugs    Creative writing    Tournaments       Ride share to tournaments Improve Your Game    Game Analysis    Study Group    Teachers/Club Leaders       Teacher advertisements    Study Journals L19²GO (Malkovich)    1-on-1 Malkovich games    Big Brother Malkovich games    Rengo Games    Other versions of turn-based games Go Gear    Go Books    Go Book Reviews    Computer Go    Gobans and other equipment    Trading Post    New Products/Upgrades/Sales Go Club Forums    Go Club Discussions       Honinbo Go League    American Go Association Forum       Go Congress 2011 volunteers       AGA volunteers ( non-congress)    Australian Go Association    European Go Federation Forum    Singapore Weiqi Association    KGS    ASR League    IGS    OGS    Tygem    WBaduk    Turn Based Servers    Insei League Events    Kaya.gs       King of the Hill