SoDesuNe paves his road to Shodan

[SoDesuNe]

Re: 185

Presumably you refer to P1 being better than Q1, but why? With P1, white can play Q1. If black wishes to avoid seki, he must fill T3. White gets T6 sente. Then black must fill T1. White en has T5 sente. Black captures at R1. Net result: black captures 6 stones and has point at S4 for 13 points, and white has a capture for a net of 12 points.

Contrast this with Q1. White T6 can be responded to with T5, and black no longer must fill T3 and T1 to avoid seki. Black has 5 captures plus S4, T3, and P1, giving 13 points. Similar result if white captures at P1.

I think Q1 is better. Does this analysis differ from yours?

You are right, I did not check what's better point-wise before ^^ I thought P1 is cleaner somehow, maybe there is Aji when White gets stones from the left? I don't know, P1 struck me as odd :o

[Kirby]

I thought about this a little more, and it's interesting to consider which of the two moves are more "optimal".

My initial thoughts were based on points - namely, with the book answer, you can avoid seki without having to fill in your own points to capture, as described here:

Suppose we go with the suggested book alternative. White has the option of threatening seki, forcing black to capture. Black fills in two of his liberties in doing so.

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 4 |
$$ . . . . O X X X 6 |
$$ . . . X O O X . X |
$$ . . . X X X O X 3 |
$$ . . . . X O O O X |
$$ . . . . 1 2 7 O 5 |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 4 |
$$ . . . . O X X X 6 |
$$ . . . X O O X . X |
$$ . . . X X X O X 3 |
$$ . . . . X O O O X |
$$ . . . . 1 2 7 O 5 |
$$ ------------------+[/go]

6 captures + 1 point - 1 capture by white = 12 points


Alternatively, with the book solution, we don't have to fill in the marked intersections, and can avoid seki completely.

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 2 |
$$ . . . . O X X X 3 |
$$ . . . X O O X . X |
$$ . . . X X X O X C |
$$ . . . . X O O O X |
$$ . . . . . 1 X O C |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 2 |
$$ . . . . O X X X 3 |
$$ . . . X O O X . X |
$$ . . . X X X O X C |
$$ . . . . X O O O X |
$$ . . . . . 1 X O C |
$$ ------------------+[/go]

5 captures + 4 points = 14 points

Even if white captures the two stones and black throws in, it's still more than the 12 points achieved by the alternative move.

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 2 |
$$ . . . . O X X X 3 |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . 4 5 . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 2 |
$$ . . . . O X X X 3 |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . 4 5 . O . |
$$ ------------------+[/go]

6 captures + 4 points - 2 captures by white = 14 points


Ko Threats
But then we can consider the idea of ko threats. Even if we can avoid seki with more points using the book's solution, do ko threats change between the variations?

With the book alternative move...

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O . |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . 1 . X O . |
$$ ------------------+

Click Here To Show Diagram Code

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

White can use the seki-threatening move as ko threat #1, inducing black to play at the marked spot:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O . |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X C |
$$ . . . . X O O O X |
$$ . . . . X W . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O . |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X C |
$$ . . . . X O O O X |
$$ . . . . X W . O . |
$$ ------------------+[/go]

White can play his sente here for ko threat #2...

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O W |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X X |
$$ . . . . X O O O X |
$$ . . . . X O . O C |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O W |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X X |
$$ . . . . X O O O X |
$$ . . . . X O . O C |
$$ ------------------+[/go]

And here for ko threat #3. If black responds to all, white is now captured without ko threats in the area.

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X W |
$$ . . . X O O X . X |
$$ . . . X X X O X X |
$$ . . . . X O O O X |
$$ . . . . X O C O X |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X W |
$$ . . . X O O X . X |
$$ . . . X X X O X X |
$$ . . . . X O O O X |
$$ . . . . X O C O X |
$$ ------------------+[/go]

So maybe 3 ko threats or so...

Now what about the book move?

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O . |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . . 1 X O . |
$$ ------------------+

Click Here To Show Diagram Code

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

Supposing white follows the order given above to illustrate point difference, white can make a ko threat similarly to the alternative book move threat:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O W |
$$ . . . . O X X X C |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . . X X O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O W |
$$ . . . . O X X X C |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . . X X O . |
$$ ------------------+[/go]

Later, white can capture as another ko threat (#2). To avoid seki, black throws in:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . W C . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . W C . O . |
$$ ------------------+[/go]

White can threaten to move out with ko threat #3, but does black even need to answer?

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . W O X . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . W O X . O . |
$$ ------------------+[/go]

It's hard to say. Maybe if there are white stones nearby to the left, white could play like this to link up to the left of the diagram:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . W . O O X . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . W . O O X . O . |
$$ ------------------+[/go]

So maybe to prevent this, black responds to the ko threat:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . B O O X . O . |
$$ ------------------+

Click Here To Show Diagram Code

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

If there are nearby stones, then, maybe white has another ko threat here, for a 4th ko threat:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . W . X O O O X |
$$ . . B O O X . O . |
$$ ------------------+

Click Here To Show Diagram Code

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

I can't see the "3rd ko threat" in this situation as being a threat unless we know that white can get enough liberties by escaping to the left. So perhaps depending on this, white might possibly have an extra ko threat using the alternative to the book move.

In that sense, perhaps playing solidly eliminates this possible ko threat (if it exists), at the expense of the two points required to fill in order to capture and avoid seki.

In general, I like being able to keep the two points by using the book solution. However, it's true that this leaves aji and an extra possible ko threat if there are nearby friendly white stones...

Interesting problem!

[logan]

I thought about this a little more, and it's interesting to consider which of the two moves are more "optimal".

My initial thoughts were based on points - namely, with the book answer, you can avoid seki without having to fill in your own points to capture, as described here:

Suppose we go with the suggested book alternative. White has the option of threatening seki, forcing black to capture. Black fills in two of his liberties in doing so.

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 4 |
$$ . . . . O X X X 6 |
$$ . . . X O O X . X |
$$ . . . X X X O X 3 |
$$ . . . . X O O O X |
$$ . . . . 1 2 7 O 5 |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 4 |
$$ . . . . O X X X 6 |
$$ . . . X O O X . X |
$$ . . . X X X O X 3 |
$$ . . . . X O O O X |
$$ . . . . 1 2 7 O 5 |
$$ ------------------+[/go]

6 captures + 1 point - 1 capture by white = 12 points


Alternatively, with the book solution, we don't have to fill in the marked intersections, and can avoid seki completely.

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 2 |
$$ . . . . O X X X 3 |
$$ . . . X O O X . X |
$$ . . . X X X O X C |
$$ . . . . X O O O X |
$$ . . . . . 1 X O C |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 2 |
$$ . . . . O X X X 3 |
$$ . . . X O O X . X |
$$ . . . X X X O X C |
$$ . . . . X O O O X |
$$ . . . . . 1 X O C |
$$ ------------------+[/go]

5 captures + 4 points = 14 points

Even if white captures the two stones and black throws in, it's still more than the 12 points achieved by the alternative move.

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 2 |
$$ . . . . O X X X 3 |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . 4 5 . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O 2 |
$$ . . . . O X X X 3 |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . 4 5 . O . |
$$ ------------------+[/go]

6 captures + 4 points - 2 captures by white = 14 points


Ko Threats
But then we can consider the idea of ko threats. Even if we can avoid seki with more points using the book's solution, do ko threats change between the variations?

With the book alternative move...

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O . |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . 1 . X O . |
$$ ------------------+

Click Here To Show Diagram Code

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

White can use the seki-threatening move as ko threat #1, inducing black to play at the marked spot:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O . |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X C |
$$ . . . . X O O O X |
$$ . . . . X W . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O . |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X C |
$$ . . . . X O O O X |
$$ . . . . X W . O . |
$$ ------------------+[/go]

White can play his sente here for ko threat #2...

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O W |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X X |
$$ . . . . X O O O X |
$$ . . . . X O . O C |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O W |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X X |
$$ . . . . X O O O X |
$$ . . . . X O . O C |
$$ ------------------+[/go]

And here for ko threat #3. If black responds to all, white is now captured without ko threats in the area.

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X W |
$$ . . . X O O X . X |
$$ . . . X X X O X X |
$$ . . . . X O O O X |
$$ . . . . X O C O X |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X W |
$$ . . . X O O X . X |
$$ . . . X X X O X X |
$$ . . . . X O O O X |
$$ . . . . X O C O X |
$$ ------------------+[/go]

So maybe 3 ko threats or so...

Now what about the book move?

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O . |
$$ . . . . O X X X . |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . . 1 X O . |
$$ ------------------+

Click Here To Show Diagram Code

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

Supposing white follows the order given above to illustrate point difference, white can make a ko threat similarly to the alternative book move threat:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O W |
$$ . . . . O X X X C |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . . X X O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O W |
$$ . . . . O X X X C |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . . X X O . |
$$ ------------------+[/go]

Later, white can capture as another ko threat (#2). To avoid seki, black throws in:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . W C . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . . W C . O . |
$$ ------------------+[/go]

White can threaten to move out with ko threat #3, but does black even need to answer?

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . W O X . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . . W O X . O . |
$$ ------------------+[/go]

It's hard to say. Maybe if there are white stones nearby to the left, white could play like this to link up to the left of the diagram:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . W . O O X . O . |
$$ ------------------+

Click Here To Show Diagram Code

[go]$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . W . O O X . O . |
$$ ------------------+[/go]

So maybe to prevent this, black responds to the ko threat:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . . . X O O O X |
$$ . . B O O X . O . |
$$ ------------------+

Click Here To Show Diagram Code

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

If there are nearby stones, then, maybe white has another ko threat here, for a 4th ko threat:

$$Bc
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . O O O O O |
$$ . . . . O X X X X |
$$ . . . X O O X . X |
$$ . . . X X X O X . |
$$ . . W . X O O O X |
$$ . . B O O X . O . |
$$ ------------------+

Click Here To Show Diagram Code

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

I can't see the "3rd ko threat" in this situation as being a threat unless we know that white can get enough liberties by escaping to the left. So perhaps depending on this, white might possibly have an extra ko threat using the alternative to the book move.

In that sense, perhaps playing solidly eliminates this possible ko threat (if it exists), at the expense of the two points required to fill in order to capture and avoid seki.

In general, I like being able to keep the two points by using the book solution. However, it's true that this leaves aji and an extra possible ko threat if there are nearby friendly white stones...

Interesting problem!

Kirby, I'm happy that you found so much interest in a single problem. As you may have suspected, the tension between ko threats and points (and often additional aspects) is nearly universal in L&D problem books. A sign of a good L&D book is how consistently the author chooses one of these to be the right solution across all multi-solution problems. If you're joining us in the book, then you may wish to tally the author's choices and see where he finishes (something I've occasionally done in my problem books).

Perhaps you can also imagine how much more difficult these tensions are in Endgame problem books. I think it's a serious issue that authors of these books have to have settled before they get started and if they wish to publish a great book.

[Kirby]

Hi logan,
I agree with the points you make on the importance of consistency. Regarding tallying the author's choices, I don't have the book (Weiqi Life and Death 1000 Problems, right?), but perhaps I'll add it to my wishlist. Based on the senseis link you provided earlier, it looks to be a good book!

[SoDesuNe]

So far I can really recommend Weiqi Life and Death 1000 Problems. It has a lot of neat problems (close to Go/Segeo Tesuji Problems but not as big in scale obviously and comparable to Maeda's Intermediate Level Problems) and also quite a few problems I did not see (or recognized, though I'm fairly good at that) before.
Especially Killing Eyes and Capturing Races are two sections (translations from Sensei's Library) which taught me new moves (Tesujis?) I had not seen before. It's really great because the latter is a big weakness of mine.
Looking forward to the following 20 sections : D

[RBerenguel]

So far I can really recommend Weiqi Life and Death 1000 Problems. It has a lot of neat problems (close to Go/Segeo Tesuji Problems but not as big in scale obviously and comparable to Maeda's Intermediate Level Problems) and also quite a few problems I did not see (or recognized, though I'm fairly good at that) before.
Especially Killing Eyes and Capturing Races are two sections (translations from Sensei's Library) which taught me new moves (Tesujis?) I had not seen before. It's really great because the latter is a big weakness of mine.
Looking forward to the following 20 sections : D

Could I (~5k I guess) solve some of them? I love having new books

[SoDesuNe]

Hmm, I've just solved the first three sections, so I can't say for sure but I think overall it's too hard for 5-kyu. On Sensei's Library logan estimated the book around 1-kyu to 3-dan, I think that fits quite well.

[RBerenguel]

4 stones to go then!

[SoDesuNe]

I just replayed the first game of Chen Yaoye's fourth Tianyuan defence and I couldn't help myself, I needed to put down my awe in some comments : D

(;GM[1]FF[4]CA[UTF-8]AP[CGoban:3]ST[2]
RU[Japanese]SZ[19]KM[7.50]
PW[Chen Yaoye]PB[Gu Lingyi]BR[5d]DT[2013-05-13]EV[27th Tianyuan title match 1]C[This game is the first of two games where Chen Yaoye defends his title (Tianyuan, the chinese version of the japanese Tengen).

I read several times (GoGameGuru, Sensei's Libary) that Chen Yaoye likes to play solid, even opting for seemingly slow moves and is very good at reading, especially at Sabaki. For me this game is exactly the essence of Chen Yaoye's style - perfectly executed.]RE[W+Resign]
;B[pd]
;W[dd]
;B[qp]
;W[dq]
;B[do]
;W[cm]
;B[cq]
;W[gq]
;B[fp]LB[er:A]C[SoDesuNe:
Interesting move, never saw this one before. A database research (GoGoD Summer 2012) shows five pro games since 2009 and A was played exclusively in answer to the marked move.
But this - I guess - not-yet-Joseki is evolving and changing very fast.]
;W[cr]
;B[fq]
;W[dp]
;B[cn]
;W[dm]
;B[cp]
;W[eo]
;B[br]
;W[er]
;B[cs]
;W[fr]
;B[dr]
;W[gp]
;B[nq]C[SoDesuNe:
Black follows common opening theory and counters White's stength with his large Shimari.]
;W[dn]C[SoDesuNe:
White opts for stability and kills off all Aji in his position. In Gote. In the opening. We will see the benefit of that later on.]
;B[co]
;W[fo]
;B[nc]C[SoDesuNe:
Black again follows common opening theory and takes another big point, this time at the top.

Here is a nice discussion between Bill Spight and lovelove, regarding this move and traditional and modern style of play: viewtopic.php?f=10&t=7890]
;W[qj]C[SoDesuNe:
Naturally White splits the side.]
;B[qh]
;W[qm]
;B[fc]
;W[cf]
;B[id]
;W[qf]LB[kc:A][kd:B]C[SoDesuNe:
With White's stable group below this seems the most reasonable invasion - and settling towards the corner is also the easiest. As the weak player I am, my eyes shifted to A or B instead.]
;B[oh]
;W[qd]C[SoDesuNe:
The attachment is natural, White wants to settle himself quickly.]
;B[qc]
;W[rc]
;B[pc]LB[id:C][pe:B][re:A][dn:1][fo:2]TR[oh][qh]C[SoDesuNe:
In response to Black's move, White A is a very common choice. But here the marked stones nearby do not allow such play, I think. After A, Black can force B and connect his stones, building quite the impressive wall with C in a perfect place.

But, if we think back to White's play in the bottom left (1 and 2). White has opted for stability, so he can play a much stronger move now.]
;W[pe]
;B[rd]
;W[re]C[SoDesuNe:
It's a Ko!

In a game from 2010 against Anzai Nobuaki, where the local situation was similar, Chen Yaoye played exactly the same.]
;B[qe]
;W[qq]
;B[pq]
;W[qd]
;B[pk]
;W[sd]
;B[qk]C[SoDesuNe:
My weak Go-skills saw White crumble here. But Chen Yaoye beatifully took every ounce of Aji in this position and outplayed Black.]
;W[pp]C[SoDesuNe:
Cross-cut! Sure, I can understand that, being the number one Tesuji to try to settle quickly.]
;B[qo]
;W[po]
;B[pr]C[SoDesuNe:
Strong counter, gives White the least play (forcing moves).]
;W[np]
;B[mp]
;W[no]
;B[lq]
;W[rk]C[SoDesuNe:
Now it's getting larger in scale.]
;B[qn]
;W[pn]
;B[rm]
;W[rl]
;B[ql]
;W[pm]
;B[rn]C[SoDesuNe:
Suddenly Black doesn't look as intimidating anymore.]
;W[pj]
;B[ok]
;W[oj]LB[oh:4][pj:3][pk:2][pm:1]C[SoDesuNe:
At first I was reminded of Opening Theory Made Easy and "Harming your own stones" since it looks like White is strengthening Black's cutting stones and is killing his stones below.
Then I saw that Black can't really attack White below because his cutting stones are weak themselves, they need to run right now. Black has a weak sandwich group which makes White's groups on both side stronger (or maybe a bit safer).

To top that, it's essentially a battle between four groups!]
;B[nk]
;W[nj]
;B[mj]
;W[mi]
;B[mk]
;W[ln]LB[mk:1][ln:2]C[SoDesuNe:
Now is a good time to play from this group. You can say 1 induced 2 - good style!

Beware! This group does not run! It cuts Black and attacks the cutting stones while getting out in the open.]
;B[ni]
;W[ph]C[SoDesuNe:
Tesuji! White is connected.]
;B[km]
;W[kn]
;B[mm]
;W[kp]
;B[mh]
;W[pg]
;B[li]C[SoDesuNe:
Capturing is common sense. And what is White's next move?]
;W[kq]C[SoDesuNe:
Right! Stability! (I would call it Honte but I'm too confused due to recent discussion about the term to know what Honte really is ^^)]
;B[dg]C[SoDesuNe:
Here I found White's move order pretty neat. What would you play?]
;W[ec]C[SoDesuNe:
First, defend the corner. Or stability - ohyay!]
;B[fd]
;W[df]C[SoDesuNe:
Then counterattack!]
;B[eg]
;W[ef]
;B[fg]
;W[ff]
;B[gg]
;W[gf]
;B[hf]
;W[ne]
;B[me]
;W[he]
;B[ie]
;W[mf]
;B[nd]
;W[le]
;B[md]
;W[mg]
;B[oe]
;W[nf]C[SoDesuNe:
That's - in my eyes - ugly shape that cries Ko but Chen Yaoye with safe groups all over the place seems to know what he is doing.]
;B[fb]
;W[eb]
;B[jm]
;W[lr]
;B[mr]
;W[lp]
;B[mq]
;W[kg]
;B[ig]
;W[fa]
;B[ga]
;W[ea]
;B[hb]
;W[ch]
;B[of]
;W[og]
;B[ng]LB[od:A][pf:B]C[SoDesuNe:
A wild Ko emerges! But it actually isn't such a burden for White since he has two local threats.]
;W[nh]
;B[cg]
;W[bg]
;B[ng]
;W[od]
;B[oc]
;W[nh]
;B[rj]
;W[ri]
;B[ng]
;W[pf]
;B[od]
;W[nh]
;B[mo]
;W[mn]
;B[ng]
;W[hh]
;B[hg]
;W[nh]
;B[nm]
;W[nn]
;B[ng]
;W[rq]
;B[rp]
;W[nh]
;B[bh]
;W[bi]
;B[ng]
;W[oq]
;B[or]
;W[nh]
;B[dh]
;W[oi]
;B[ci]C[SoDesuNe:
Now we could say, Black is one move away from a well sized center.]
;W[hl]C[SoDesuNe:
Bam!]
;B[in]
;W[ik]TR[mh][li][ni][mj][mk][nk][ok][pk][qk][ql][jm][km][mm][nm][in]C[SoDesuNe:
And suddenly, White isn't just reducing Black's center potential but attacking the marked group!]
;B[kk]
;W[ld]
;B[lc]
;W[qb]
;B[pb]
;W[ra]
;B[ke]LB[kc:A]C[SoDesuNe:
I really like White's endgame play here, threatening A. This black move, which prevents A, is also quite something.]
;W[so]C[SoDesuNe:
Again very good endgame by White!]
;B[sp]
;W[bf]
;B[bj]
;W[hn]C[SoDesuNe:
Wait, wasn't there an emerging Black center before? Now White makes points in the center?

Do you want to tell me with safe groups you can pick up points anywhere, completely troublefree?]
;B[ho]
;W[im]
;B[gn]
;W[hm]
;B[go]
;W[fm]
;B[jn]
;W[io]
;B[gr]
;W[hr]LB[hq:A]C[SoDesuNe:
There's actually quite some Aji when Black cuts with A now. But as I see it, it does not work with proper White play. What do you think? =)


END OF COMMENTS.])

Record form http://igokisen.web.fc2.com/cn/tn.html

[SoDesuNe]

I completed section five (Seki) from Weiqi Life and Death 1000 Problems a while ago and as christmas holidays draw nearer my anual Go hiatus arrived ^^ So, I didn't start section six, yet. I guess this won't change until January.

The dark times are reserved for (fictional) books and videogames =D

I also thought about starting a new study journal since I am now Shodan on two accounts (you can even see the rank in graph in the first post ^^) but I guess, I try to make Nidan first. That way I'm completely sure I'm at least Shodan : D

[Kirby]

...

The dark times are reserved for (fictional) books and videogames =D
...

Any book recommendations?

[SoDesuNe]

Hm, I guess this is difficult because at the moment I am catching up on older books ^^
I have yet to finish Stephen King's Dark Tower series, right now I'm at the last book. Then there is a german fantasy series called "Mara und der Feuerbringer", which comes on the big screen next year, as far as I know. Furthermore I plan on purchasing "Ender's Game", because I heard - as always - you should read the book instead of watching the movie : D

That's what's in my head for now ^^

[SoDesuNe]

Except for reviewing, I didn't study any Go books since my last post in this thread.

Hitting and maintaining Shodan (if ever so briefly because I stopped a few weeks after that) seems to have quite the psychological effect on me. Understandably if I look at how long this was my goal. I think it's time for something fresh and new.

I still visit the weekly Go club and I got definitely weaker (strategy, oh, where are thou?). But since I started playing chess (again), learning C# and generally feast upon math (projecteuler.net ftw!) and physics this should come as no surprise. (So problem solving is still my number one interest but in different fields : D)
Luckily the whole Go club is pretty much a gathering of programmers, math and physics students and chess players and trainers.

All that's left now is concluding with the famous Captain Jack Sparrow quote: "Bring me that horizon!"

[Ember]

Hitting and maintaining Shodan (if ever so briefly because I stopped a few weeks after that) seems to have quite the psychological effect on me. Understandably if I look at how long this was my goal. I think it's time for something fresh and new.

I know exactly what you mean. I've been 6kyu (including weaker peroids of time) for more than four years and since I was finally able to promote myself to 5kyu recently, I experienced the exact same thing. It sounds like your interest has shifted to some other fields for now and forcing yourself to do more related to Go probably wouldn't be that productive. Maybe you have to wait a little more for the motivation to come back? I'm sure there'll be better times to come when the fire is burning bright again and you'll not only catch up with your old strength, but get stronger than before. Until then I'll come back to read some old entries of your journal, which, by the way, is really inspiring.

[SoDesuNe]

Thank you very much, that's nice to hear =)

I certainly learnt a lot along the way.