Life In 19x19

I see that I somehow messed up the SGF file with my comments. Corrected now.

Yes, I see there is more comments now. It is particularly painful to see that I actually could have taken that top right corner. I gave up there thinking there wasn't a way.

mongus wrote:Yes, I see there is more comments now. It is particularly painful to see that I actually could have taken that top right corner. I gave up there thinking there wasn't a way.

That corner would have defeated much stronger players than you.

But now you know. Snapbacks are powerful.

Here's a mistake I just made in a 9x9.

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O . . . . . |
$$ O X X X X O . |
$$ , O O X O O . |
$$ . . . O X X . |[/go]

I am black. I think, great - this should be easy. I have three liberties, my opponent has three liberties. It's my move. An easy race. I'm going to enjoy winning this one.

So I start the race.

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O . . 2 a . |
$$ O X X X X O b |
$$ , O O X O O 1 |
$$ . . . O X X . |[/go]

Darn it. My opponent plays at 2. This means if I play at a, my stone will be in atari,and will easily be killed. So I have to play at b, allowing white to play at a.

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O . . O O a |
$$ O X X X X O X |
$$ , O O X O O X |
$$ . . . O X X b |[/go]

Now, if I play at a those two stones will be in atari and dead. So I have to play at b. This extra move I have to make allows White to take an extra liberty from my group and kill those stones. The game belongs to white.


What I should have done is played here first :

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O . . . 1 . |
$$ O X X X X O . |
$$ , O O X O O . |
$$ . . . O X X . |[/go]

That way this stone could have provided support for the group I am defending whilst attacking my opponents stones.

Lesson learned.

Hi mongus,

Good study.

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O . c O W a |
$$ O X X X X O X |
$$ , O O X O O X |
$$ . . . O X X b |[/go]

Yup. "b" is a liberty for the five White stones when Black cannot afford to atari at "c". The stone on the 2-1 point is key.

Good lesson.

Another painful lesson today about leaving gaps in my defences.

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . .
$$ | O O O O . . .
$$ | X X X X O . .
$$ | . X . X a b .
$$ | X X X O c . .
$$ | O O O . . . .
$$ | . . . . . . .[/go]

I am white. I failed to kill this group. But luckily I managed to contain it.. or so I thought. I failed to see the significance of that gaping wide hole in my defence. I casually thought if Black plays at a I can just block at b or something.. Although on reflection even that wouldn't have worked. I played elsewhere and didn't cover this gap.

Instead Black played at c, putting my stone in atari. Whilst I was covering this stone Black escaped and caused mayhem.

I should have just covered a. Then my opponent would have been stuck with very little territory.

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . .
$$ | O O O O . . .
$$ | X X X X O . .
$$ | . X . X O . .
$$ | X X X O . . .
$$ | O O O . . . .
$$ | . . . . . . .[/go]

mongus wrote:Another painful lesson today about leaving gaps in my defences.

$$B
$$ | . . . . . . .
$$ | O O O O . . .
$$ | X X X X O . .
$$ | . X . X a b .
$$ | X X X O c . .
$$ | O O O . . . .
$$ | . . . . . . .

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . .
$$ | O O O O . . .
$$ | X X X X O . .
$$ | . X . X a b .
$$ | X X X O c . .
$$ | O O O . . . .
$$ | . . . . . . .[/go]

I am white. I failed to kill this group. But luckily I managed to contain it.. or so I thought. I failed to see the significance of that gaping wide hole in my defence. I casually thought if Black plays at a I can just block at b or something.. Although on reflection even that wouldn't have worked. I played elsewhere and didn't cover this gap.

Instead Black played at c, putting my stone in atari. Whilst I was covering this stone Black escaped and caused mayhem.

I should have just covered a. Then my opponent would have been stuck with very little territory.

$$B
$$ | . . . . . . .
$$ | O O O O . . .
$$ | X X X X O . .
$$ | . X . X W . .
$$ | X X X O . . .
$$ | O O O . . . .
$$ | . . . . . . .

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . .
$$ | O O O O . . .
$$ | X X X X O . .
$$ | . X . X W . .
$$ | X X X O . . .
$$ | O O O . . . .
$$ | . . . . . . .[/go]

We cannot evaluate a play at without seeing the surroundings. has no effect on the Black group, and we do not know what effect it has elsewhere. Confining a group to force it to make small life in gote is usually good. How good is it to take gote to confine a living group? Who knows?

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . .
$$ | O O O O . . .
$$ | X X X X O . .
$$ | . X . X O . .
$$ | X X X O 2 . .
$$ | W W W 1 . . .
$$ | . . . 3 . . .
$$ | . . . . . . .[/go]

In this case the surrounding stones have three cutting points which Black might take advantage of. For instance, Black might play - , putting the three marked stones in jeopardy.

Hi mongus,

As Bill says, we need to see the whole board to evaluate the situation.

But locally, please see again toothpaste and related pages.

You have already moved on but I want to briefly return to your previous topic:

mongus wrote:What I should have done is played here first :

$$B
$$ --------------+
$$ . O . . . 1 . |
$$ O X X X X O . |
$$ , O O X O O . |
$$ . . . O X X . |

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O . . . 1 . |
$$ O X X X X O . |
$$ , O O X O O . |
$$ . . . O X X . |[/go]

Nicely learned! As a simple coda, what do you do now?

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O . . . 1 . |
$$ O X X X X O 2 |
$$ , O O X O O . |
$$ . . . O X X . |[/go]

That way this stone could have provided support for the group I am defending whilst attacking my opponents stones.

I would be careful about phrasing the role of that way. It might lead you to think that you should play inside rather than outside during a capturing race as a general rule, when in fact you more often want to do the opposite (since playing inside often decreases your own liberties as well).

The lessons I would take from this example are:

• Required approach moves are just as good as liberties, since they consume an extra turn.
• Approach moves more likely to be necessary on the side than in the center.
• Approach moves are even more likely to be necessary in the corner

Bill Spight wrote:
We cannot evaluate a play at without seeing the surroundings. has no effect on the Black group, and we do not know what effect it has elsewhere. Confining a group to force it to make small life in gote is usually good. How good is it to take gote to confine a living group? Who knows?

Good point. So if I had had some other killer move instead of it would have been worth playing. In this case I don't think I did. I attacked another corner, which did result in me having a fairly decent wall facing the centre. But I think that attack could have waited another turn whilst I played at . Had I done this I would have had a strong wall on the whole bottom side. Instead White spilled out and gained quite a lot of influence in the centre - nicely secured by his two eyes.

I'm still in the middle of the game (its on the Dragon Go Server), but I will post it here when it is finished.

Bill Spight wrote:

$$B
$$ | . . . . . . .
$$ | O O O O . . .
$$ | X X X X O . .
$$ | . X . X O . .
$$ | X X X O 2 . .
$$ | W W W 1 . . .
$$ | . . . 3 . . .
$$ | . . . . . . .

Click Here To Show Diagram Code

[go]$$B
$$ | . . . . . . .
$$ | O O O O . . .
$$ | X X X X O . .
$$ | . X . X O . .
$$ | X X X O 2 . .
$$ | W W W 1 . . .
$$ | . . . 3 . . .
$$ | . . . . . . .[/go]

In this case the surrounding stones have three cutting points which Black might take advantage of. For instance, Black might play - , putting the three marked stones in jeopardy.

Interesting point. I wouldn't have spotted that until it was too late. In the actual game, I actually have a stone at 3, so that wouldn't have been possible - but it is a lesson that really there is much more that can go on that I am not quite aware of yet.

EdLee wrote:Hi mongus,

As Bill says, we need to see the whole board to evaluate the situation.

But locally, please see again toothpaste and related pages.

Yes, squeezing toothpaste is one of my hardest lessons to take on so far. The whole situation here occurred because I played too close too early on in the game, resulting in a needless fight.

dfan wrote:You have already moved on but I want to briefly return to your previous topic:

dfan wrote: I'm still working through stuff from page 1 of this thread.
Nicely learned! As a simple coda, what do you do now?

$$B
$$ --------------+
$$ . O . . . 1 . |
$$ O X X X X O 2 |
$$ , O O X O O . |
$$ . . . O X X . |

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O . . . 1 . |
$$ O X X X X O 2 |
$$ , O O X O O . |
$$ . . . O X X . |[/go]

I presume something like the following :

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O 4 . . 1 . |
$$ O X X X X O 2 |
$$ , O O X O O 5 |
$$ . . . O X X 3 |[/go]

[/quote]

dfan wrote:

That way this stone could have provided support for the group I am defending whilst attacking my opponents stones.

I would be careful about phrasing the role of that way. It might lead you to think that you should play inside rather than outside during a capturing race as a general rule, when in fact you more often want to do the opposite (since playing inside often decreases your own liberties as well).

The lessons I would take from this example are:

• Required approach moves are just as good as liberties, since they consume an extra turn.
• Approach moves more likely to be necessary on the side than in the center.
• Approach moves are even more likely to be necessary in the corner

I wasn't aware that these were called approach moves. Thanks. Have consequently found more on http://senseis.xmp.net/?ApproachMove.

mongus wrote:I presume something like the following :

$$B
$$ --------------+
$$ . O 4 . . 1 . |
$$ O X X X X O 2 |
$$ , O O X O O 5 |
$$ . . . O X X 3 |

Click Here To Show Diagram Code

[go]$$B
$$ --------------+
$$ . O 4 . . 1 . |
$$ O X X X X O 2 |
$$ , O O X O O 5 |
$$ . . . O X X 3 |[/go]

Yup. I actually thought when I asked this last night that this was trickier because to the left of would have gotten you captured, but White has to make approach moves too!

Bill Spight wrote: We cannot evaluate a play at without seeing the surroundings. has no effect on the Black group, and we do not know what effect it has elsewhere. Confining a group to force it to make small life in gote is usually good. How good is it to take gote to confine a living group? Who knows?

Have finished the game where I made this mistake. It turns out that I actually won it in the end!!

Move 50 is where the board in question occurred where I should have covered that gap.