Life In 19x19 :: L19 Go Problem Championship: Round 8

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L19 Go Problem Championship: Round 8 http://lifein19x19.com/viewtopic.php?f=15&t=14158	Page 1 of 1

Author: Kirby [ Sun Apr 09, 2017 8:29 pm ]

Post subject: L19 Go Problem Championship: Round 8

Welcome to Round 8 of the L19 Go Problem Championship.

All problems are black to play. As usual, provide your solutions either via hide tags, or direct private message to me.

Problem 1 (3 points)

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

Problem 2 (6 points)

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

Problem 3 (9 points)

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

Have fun!

Author:	EdLee [ Mon Apr 10, 2017 2:51 am ]
Post subject:
Click Here To Show Diagram Code `[go]$$B Life $$ ----------------- $$ \| . 1 . O . . . . $$ \| X O X X O . . . $$ \| . . X O . O . . $$ \| X X O O . . . . $$ \| O O . . . . . . $$ \| . . . . . . . .[/go]` Click Here To Show Diagram Code `[go]$$B Oops $$ ----------------- $$ \| . 2 . O . . . . $$ \| X O X X O . . . $$ \| . 1 X O . O . . $$ \| X X O O . . . . $$ \| O O . . . . . . $$ \| . . . . . . . .[/go]` First feeling: Click Here To Show Diagram Code `[go]$$B $$ ----------------------- $$ . . . . . X . . . . . \| $$ . . O 1 . O X X . X O \| $$ . O . O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` Click Here To Show Diagram Code `[go]$$B $$ \| . . . . . . . . . . . $$ \| . O O O O . . . . . . $$ \| . X O X X O O O O . . $$ \| . O . , . X X . . O . $$ \| O . X . . O . X X O . $$ \| . O X O . . . . . O . $$ \| . O . . . . . X . O . $$ -----------------------[/go]`

Author:	Schachus [ Mon Apr 10, 2017 5:58 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
Kirby wrote: Welcome to Round 8 of the L19 Go Problem Championship. Problem 1 (3 points) Click Here To Show Diagram Code `[go]$$Bc $$ ---------------- $$ \| . . . O . . . . $$ \| X O X X O . . . $$ \| . . X O . O . . $$ \| X X O O . . . . $$ \| O O . . . . . . $$ \| . . . . . . . .[/go]` Click Here To Show Diagram Code `[go]$$Bc $$ ---------------- $$ \| a 1 . O . . . . $$ \| X O X X O . . . $$ \| . . X O . O . . $$ \| X X O O . . . . $$ \| O O . . . . . . $$ \| . . . . . . . .[/go]` 2 eyes at a and where the white stone is. The following would be wrong: Click Here To Show Diagram Code `[go]$$Bc $$ ---------------- $$ \| . 2 b O . . . . $$ \| X O X X O . . . $$ \| . 1 X O . O . . $$ \| X X O O . . . . $$ \| O O . . . . . . $$ \| . . . . . . . .[/go]` and black cant block at b due to shortage of liberties Quote: Problem 2 (6 points) Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . . . X . . . . . \| $$ . . O . . O X X . X O \| $$ . O . O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` It would appear, I had a lot of miscalculations in problem 2 and I should clear up my thoughts before posting. For problem 3, I need to consider it for a while... Edit: ooops, this was unhidden, because I meant to send it as a PM to Kirby... I hope nobody saw it, I'm sorry

Author:	mongus [ Tue Apr 11, 2017 5:38 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
Problem 1 Click Here To Show Diagram Code `[go]$$Bc $$ ---------------- $$ \| . 1 3 O 2 . . . $$ \| X O X X O . . . $$ \| . . X O . O . . $$ \| X X O O . . . . $$ \| O O . . . . . . $$ \| . . . . . . . .[/go]` Problem 2 Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . 3 . X . . . . . \| $$ . . O 1 2 O X X . X O \| $$ . O 5 O 4 O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` or Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . 2 . X . . . . . \| $$ . . O 1 3 O X X . X O \| $$ . O 5 O 4 O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]`

Author:	Cassandra [ Tue Apr 11, 2017 7:57 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@ mongus Problem 2 Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . 4 3 . X . . . . . \| $$ . . O 1 2 O X X . X O \| $$ . O . O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` Did you consider White's descent to 4 at the left ?

Author:	Bill Spight [ Tue Apr 11, 2017 8:21 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@mongus I see that Cassandra beat me to it. Here is another thought. Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . . 2 X . . . . . \| $$ . . O 1 . O X X . X O \| $$ . O . O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]`

Author:	Kirby [ Tue Apr 11, 2017 9:04 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@EdLee: Looking good so far. I'll wait for elaboration on the second two. @Schachus: Problem 1 looks good. @mongus: Looks good so far. Do you have a response for either of Cassandra's or Bill's replies?

Author:	mongus [ Wed Apr 12, 2017 12:12 pm ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@Bill Good question, I thought it was easy : Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . . 2 X 4 . . . . \| $$ . . O 1 . O X X . X O \| $$ . O . O 3 O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` ad then Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . 7 O 6 O . . . . \| $$ . . O X 5 O X X . X O \| $$ . O . O X O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` But then I realised White could try to be clever, Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . 6 O 7 O . . . . \| $$ . . O X 5 O X X . X O \| $$ . O . O X O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . O O . O . . . . \| $$ . . O X X 8 X X . X O \| $$ . O . O X . X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` All the white stones are connected to the outside. But eventually I noticed this : Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . 6 O . O . . . . \| $$ . . O X 5 O X X . X O \| $$ . O 7 O X O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` This gives me one eye. If White tries to take my other one, I can kill them all : Click Here To Show Diagram Code `[go]$$Wc $$ --------------------- $$ . . . O O . O . 1 . . \| $$ . 2 O X X O X X . X O \| $$ . O X . X O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` If she doesn't : Click Here To Show Diagram Code `[go]$$Wc $$ --------------------- $$ . . . O O . O . 2 . . \| $$ . 1 O X X O X X . X O \| $$ . O X . X O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` I take the eye. @Cassandra - I am still contemplating your conundrum..

Author:	mongus [ Wed Apr 12, 2017 12:25 pm ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@Cassandra That perplexed me, but I think I have it Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . 4 3 6 X 5 . . . . \| $$ . . O 1 2 O X X . X O \| $$ . O . O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` White has to play 6, otherwise I can connect and then capture the three stones. This gives me time to play in the vital spot to take my eyes : Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . O . O X X . 7 . . \| $$ . . O . O O X X . X O \| $$ . O . O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]`

Author:	Cassandra [ Wed Apr 12, 2017 1:17 pm ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@ mongus Well done ! However, ... mongus wrote: ... If she doesn't : Click Here To Show Diagram Code `[go]$$Wc $$ --------------------- $$ . . . O O . O . 2 . . \| $$ . 1 O X X O X X . X O \| $$ . O X . X O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` I take the eye. Click Here To Show Diagram Code `[go]$$Wc $$ --------------------- $$ . . . O O . O . . . . \| $$ . 1 O X X O X X . X O \| $$ . O X . X O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` I want to live with more than only three points of territory ! + + + + + + + + + + + EDIT: As Bill showed you the answer -- in principle -- in his posting below: From here on, realizing that White suffers from a shortage of liberties at the top, enabling you to capture three of her stones, very likely you would have found out that you could capture these stones a bit earlier. Such a shortage of liberties is very important, but apparently often some kind of blind spot

Author:	Bill Spight [ Wed Apr 12, 2017 1:27 pm ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@mongus Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . 6 2 . 4 7 . . . \| $$ W . O 1 5 O X X . X O \| $$ . O . O 3 O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` One to remember. Note that it works even if White has the stone. Click Here To Show Diagram Code `[go]$$Wc $$ --------------------- $$ . . . O O . O . 2 . . \| $$ . 1 O X X O X X . X O \| $$ . O X . X O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` Note that is unnecessary.

Author:	mongus [ Thu Apr 13, 2017 2:57 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@Bill and @Cassandra Thankyou, very insightful. Yes, liberty shortage problems seem to be the ones I understand the least.

Author:	hyperpape [ Thu Apr 13, 2017 7:12 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
Problem 1 Click Here To Show Diagram Code `[go]$$Bc $$ ---------------- $$ \| . 1 . O . . . . $$ \| X O X X O . . . $$ \| . . X O . O . . $$ \| X X O O . . . . $$ \| O O . . . . . . $$ \| . . . . . . . .[/go]` Problem 2 My thought was: Black threatens to make two eyes. Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . b . X 1 . 2 . . \| $$ . . O 3 a O X X . X O \| $$ . O d O c O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` a is met by b, c by d. However, we have to verify that there are two eyes after the capture. Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . . . X 1 . 2 4 . \| $$ . . O 3 . O X X . X O \| $$ . O 5 O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . 5 . X 1 . 2 . . \| $$ . . O 3 4 O X X . X O \| $$ . O 6 O 7 O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]`

Author:	hyperpape [ Thu Apr 13, 2017 7:12 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
Problem 1 Click Here To Show Diagram Code `[go]$$Bc $$ ---------------- $$ \| . 1 . O . . . . $$ \| X O X X O . . . $$ \| . . X O . O . . $$ \| X X O O . . . . $$ \| O O . . . . . . $$ \| . . . . . . . .[/go]` Problem 2 My thought was: Black threatens to make two eyes. Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . b . X 1 . 2 . . \| $$ . . O 3 a O X X . X O \| $$ . O d O c O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` a is met by b, c by d. However, we have to verify that there are two eyes after the capture. Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . . . X 1 . 2 4 . \| $$ . . O 3 . O X X . X O \| $$ . O 5 O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` Black is dead on this line. Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . 5 . X 1 . 2 . . \| $$ . . O 3 4 O X X . X O \| $$ . O 6 O 7 O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]`

Author:	Kirby [ Thu Apr 13, 2017 7:22 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@hyperpape: (Includes hint) Problem 1 is correct; Problem 2 is close. Think about the ordering of your sequence.

Author:	gamesorry [ Fri Apr 14, 2017 12:54 am ]
Post subject:	Re: L19 Go Problem Championship: Round 8
Click Here To Show Diagram Code `[go]$$Bc $$ ---------------- $$ \| . 1 . O . . . . $$ \| X O X X O . . . $$ \| . . X O . O . . $$ \| X X O O . . . . $$ \| O O . . . . . . $$ \| . . . . . . . .[/go]` 2. Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . 4 3 6 X 5 . 7 . . \| $$ . . O 1 2 O X X . X O \| $$ . O . O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` Variation: Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . 4 3 7 X 5 . 6 . . \| $$ . . O 1 2 O X X . X O \| $$ . O . O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]` Variation: Click Here To Show Diagram Code `[go]$$Bc $$ --------------------- $$ . . . . 2 X 3 . 4 . . \| $$ . . O 1 5 O X X . X O \| $$ . O . O . O X . X X O \| $$ . O X X X X X O X O . \| $$ . O O O O O O . O O . \| $$ . . . . . . . . . . . \|[/go]`

Author:	Kirby [ Sun Apr 16, 2017 10:15 pm ]
Post subject:	Re: L19 Go Problem Championship: Round 8
@gamesorry: Looks correct.

Author:	Kirby [ Sun Apr 16, 2017 10:22 pm ]
Post subject:	Re: L19 Go Problem Championship: Round 8
Solutions and updated leader board are given below. Problem 1 Problem 2 Problem 3 Leaderboard gamesorry - 110 Schachus - 68 EdLee - 66 dfan - 52 Shaddy - 49 hyperpape - 23 mongus - 19 Lanrose - 16 jeromie - 13

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