Reverse-engineering tsumego.

Post by **Solomon** » Fri Jun 27, 2014 3:12 pm

While the real benefit out of studying tsumego is to sharpen your reading skill rather than imagining the problem to be a realistic scenario that could be reverse engineered, it can be more motivating if the latter were true. For instance, maybe for this problem:

Click Here To Show Diagram Code: [go]$$Wc $$ ------------------- $$ | . . . . . . . . . $$ | . . . . O . . . . $$ | . . X X O . . . . $$ | . O X O . O . . . $$ | X . X O . . . . . $$ | . X O . . . . . . $$ | . O O . . . . . . $$ | . . . . . . . . . $$ | . O . . . . . . . $$ | . . . . . . . . .[/go]

Maybe what happened is that Black made a 3-3 invasion of White's corner:

Click Here To Show Diagram Code: [go]$$Bc $$ ------------------- $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . B . . . . . . $$ | . . . O . . . . . $$ | . . . . . . . . . $$ | . . O . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . .[/go]

And the following sequence occurs:

Click Here To Show Diagram Code: [go]$$Wc $$ ------------------- $$ | . . . . . . . . . $$ | . . . . 1 . . . . $$ | . . X . . . . . . $$ | . . 2 O . . . . . $$ | 8 . 6 3 . . . . . $$ | . 4 O . . . . . . $$ | . 5 7 . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . .[/go]

Later, elsewhere on the board a ko fight arises and B plays

as a threat, to which W responds.

Click Here To Show Diagram Code: [go]$$Bc $$ ------------------- $$ | . . . . . . . . . $$ | . . . . O . . . . $$ | . . X 1 2 . . . . $$ | . 4 X O . b . . . $$ | X . X O . . . . . $$ | . X O . . . . . . $$ | . O O . . . . . . $$ | . . . . . . . . . $$ | . a . . . . . . . $$ | . . . . . . . . .[/go]

Later on, W realizes that she is behind and eyes the corner to see if there is a way to kill it, playing

. Thinking of the problem in this light, one could ask themselves...

How does Black refute and live? (original problem statement)
If W hadn't played , could she kill this corner?
The difference between this position and the first diagram is that W had stones in a and b. Do they make a difference?

Anyways, this is just my little way of making tsumego solving a more immersive experience. How would you answer these questions? Any other interesting examples would be great, below is another problem that looks reverse-engineerable:

Click Here To Show Diagram Code: [go]$$Wc $$ ------------------- $$ | . . . . . . . . . $$ | . . . O . . . . . $$ | . . X O X . X . . $$ | . X O X . . . . . $$ | . O O X . X . . . $$ | . . . O X . . . . $$ | . . O . O . . . . $$ | . . . . . . . . . $$ | . . . . . . . . . $$ | . . . . . . . . .[/go]

Krama · Post by **Krama** » Fri Jun 27, 2014 3:35 pm

Shouldn't

be at B15?

I am not good with this stuff, perhaps I am wrong.

Mike Novack · Post by **Mike Novack** » Fri Jun 27, 2014 6:56 pm

I have certainly seen this done in books. A problem is presented. Afterwords, based on the premise "if there is a difficulty, the mistake may be earlier", the formation is shown a move before the situation of the previous problem (the move that created the opportunity of the previous problem was wrong; what move should have been made instead).

cyclops · Post by **cyclops** » Sat Jun 28, 2014 5:05 pm

Araban wrote:While the real benefit out of studying tsumego is to sharpen your reading skill rather than imagining the problem to be a realistic scenario that could be reverse engineered, it can be more motivating if the latter were true. For instance, maybe for this problem:

$$Wc
$$ -------------------
$$ | . . . . . . . . .
$$ | . . . . O . . . .
$$ | . . X X O . . . .
$$ | . O X O . O . . .
$$ | X . X O . . . . .
$$ | . X O . . . . . .
$$ | . O O . . . . . .
$$ | . . . . . . . . .
$$ | . O . . . . . . .
$$ | . . . . . . . . .
Click Here To Show Diagram Code
[go]$$Wc $$ ------------------- $$ | . . . . . . . . . $$ | . . . . O . . . . $$ | . . X X O . . . . $$ | . O X O . O . . . $$ | X . X O . . . . . $$ | . X O . . . . . . $$ | . O O . . . . . . $$ | . . . . . . . . . $$ | . O . . . . . . . $$ | . . . . . . . . .[/go]
...............( skipped by cyclops )...............
[*] If W hadn't played , could she kill this corner?

I think:

Post by **Solomon** » Sat Jun 28, 2014 9:44 pm

cyclops wrote:
Araban wrote:While the real benefit out of studying tsumego is to sharpen your reading skill rather than imagining the problem to be a realistic scenario that could be reverse engineered, it can be more motivating if the latter were true. For instance, maybe for this problem:

$$Wc
$$ -------------------
$$ | . . . . . . . . .
$$ | . . . . O . . . .
$$ | . . X X O . . . .
$$ | . O X O . O . . .
$$ | X . X O . . . . .
$$ | . X O . . . . . .
$$ | . O O . . . . . .
$$ | . . . . . . . . .
$$ | . O . . . . . . .
$$ | . . . . . . . . .
Click Here To Show Diagram Code
[go]$$Wc $$ ------------------- $$ | . . . . . . . . . $$ | . . . . O . . . . $$ | . . X X O . . . . $$ | . O X O . O . . . $$ | X . X O . . . . . $$ | . X O . . . . . . $$ | . O O . . . . . . $$ | . . . . . . . . . $$ | . O . . . . . . . $$ | . . . . . . . . .[/go]
...............( skipped by cyclops )...............
[*] If W hadn't played , could she kill this corner?
I think:
If W had played at c19 instead of at b16 she easily would have killed the corner. Later b16 is a good forcing move removing eye potential. Playing b16 first is defeated by b18. Should the conclusion be that d18 was a bad ko threat? Hmm, I am not sure that the ko exchange changed the status of the black group. Maybe its status is sente from the start.

cyclops · Post by **cyclops** » Sun Jun 29, 2014 12:59 pm

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