Life In 19x19

Hi mongus,

Continuing schawipp's notes --

Depending on the whole board situation,
here are some of the options for Black (now, or later):

Click Here To Show Diagram Code

[go]$$B
$$ ? . . . . . . . . ?
$$ ? . . . . . . . . ?
$$ ? . . . d X f . . ?
$$ ? . . e O X O b . ?
$$ ? . . O X O a . . ?
$$ ? . . . c . . . . ?
$$ ----------------[/go]

- (a) atari, then ladder with (b), if the ladder works for B (schawipp);
- (c) descend;
- (d) atari-turn on top;
- (e) atari;
- (f) turn;
- etc.

Well that is very interesting. I managed to find the game where this happened. The interesting part is move 28. The ladder would have worked very well.

mongus wrote:Well that is very interesting. I managed to find the game where this happened. The interesting part is move 28. The ladder would have worked very well.

The biggest problem in this game is the contact play of :B23:. Contact moves are usually played by the person trying to live, not by the person trying to kill. Had this stone been one point to the left there would not have been enough room for white to live. There wasn't enough room anyway, but by playing in contact you gave yourself more chance to me the type of mistake you are discussing.

mongus wrote:The interesting part is move 28.

Hi mongus,

This is good what you're doing: review your own games, looking for mistakes and better moves. Very good.

As DrStraw said, if you play this at E3, W is dead.
As homework, if you have time, prove to your satisfaction this is true.
You'll have to study and play with many variations,
with W trying to make life there, after at E3.
You must try to make the 'best' moves for W trying to live,
and B's 'best' counter. Have fun.

The descent move (c) suggested by EdLee has another meaning than just sacrifying a few more stones

With this technique you can squeeze out a white eye; depending on the exact circumstances in the surroundings, this could even kill the entire white group.

In your game example the descent seems at least making things complicated for w (look at move ):

That's very interesting. I pretty much always make contact moves - attacking or defending. Will have to study that a lot - that's quite a perspective shift!

Regarding descending from an Atari, it seems you can encourage your opponent to get into the following shape

Click Here To Show Diagram Code

[go]$$B
$$ . # O # .
$$ . O . O .
$$ . O O O .
$$ ---------[/go]

which is a dead shape. Presumably you need to have the marked stones for this to be workable, so this would only be worth pursuing if you were in this kind of situation :

Click Here To Show Diagram Code

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

(Just stating what has already been said to get it clear in my head)

mongus wrote:I pretty much always make contact moves -
attacking or defending.
Will have to study that a lot -
that's quite a perspective shift!

Hi mongus,

Yes.

One issue here is you don't (yet) differentiate between
good contact moves versus bad contact moves.
If a contact move is good, by all means play it.
If a contact move is bad (like in post 17), don't.

What's difficult is how to tell them apart.

mongus wrote:this would only be worth pursuing if you were in this kind of situation :

$$B
$$ . . O . .
$$ . O X O .
$$ . . . . .
$$ ---------

Click Here To Show Diagram Code

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

( I added the red highlight. )

Hi mongus,

In the following sequence...

Click Here To Show Diagram Code

[go]$$W :w3: tenuki
$$ | . . . . . . . .
$$ | . . X 2 . . . .
$$ | . . 1 . . . . .
$$ | . . . O 4 6 . .
$$ | . . 9 8 5 7 . .
$$ | . . . 0 . . . .
$$ | . . . . . . . .
$$ ------------------[/go]

Click Here To Show Diagram Code

[go]$$Wm11 continuing...
$$ | . . . . . . . .
$$ | . . X X . . . .
$$ | . . O 2 . . . .
$$ | . . 3 O X X 8 .
$$ | . . O X O O 4 .
$$ | . . 1 X 5 6 . .
$$ | . . . 7 . . . .
$$ ------------------[/go]

Click Here To Show Diagram Code

[go]$$W ...end of sequence
$$ | . . . . . . . .
$$ | . . X X . . . .
$$ | . . O X . . . .
$$ | . . O O X X X .
$$ | . . O . O O X .
$$ | . . O . O X . .
$$ | . . . O . . . .
$$ ------------------[/go]

Notice the cut of and the drop of .
Black planned to sacrifice not only , but also --
two stones total -- in order to get
the good sente moves , , and .
Locally, W takes the corner and B gets the outside.

You'll encounter many (more) reasons for a descent (and other moves) in your Go career.

Interesting. So in essence when you play a descend it is forcing your opponent to spend at least two moves to kill, which you can utilise to do whatever you want without being impeded.

mongus wrote:your opponent to spend at least two moves to kill

It takes only one move to remove one stone in atari,
but when you extend, depending on the local shape,
if you gain two liberties, then
it takes more than one move to capture the string.

Related to the previous, here is a recent trap I fell into. In this game :



At Move 21, White played this move

Click Here To Show Diagram Code

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

I couldn't believe my luck, thinking White must have made a terrible mistake. I just need to play at a and b and I will have killed that stone. Which I proceed to do.

However, whilst I was playing those two moves White was able to play c and d and kill my three stones.

Note, to redeem myself White tried a similar trap at Move 41. This time I played it correctly.

mongus wrote:Note, to redeem myself White tried a similar trap at Move 41. This time I played it correctly.

Well done!

This illustrates an important point. It is possible to learn while playing a game, regardless of winning or losing.

Bill Spight wrote:

mongus wrote:Note, to redeem myself White tried a similar trap at Move 41. This time I played it correctly.

Well done!

This illustrates an important point. It is possible to learn while playing a game, regardless of winning or losing.

To be honest, my opponent did warn me to be careful for move 41. I can't take all the credit!

Hi mongus,

I like to embed the actual text of the SGF directly here,
not a link to it, which is what you did in post 26.
I never have problems when I embed the text directly.
But others occasionally cannot display the game here;
please double check that your SGF post (26) works -- it didn't, as of this post.

EdLee wrote:Hi mongus,

I like to embed the actual text of the SGF directly here,
not a link to it, which is what you did in post 26.
I never have problems when I embed the text directly.
But others occasionally cannot display the game here;
please double check that your SGF post (26) works -- it didn't, as of this post.

It does say in the guidelines the preferred method is to link to it. But thats no good if you can't then see it. Have edited and embedded the SGF directly.