Weekly Go problems: Week 49

Here are the weekly Go problems for week 49.

Black plays first in all problems and all solutions are labeled ‘correct’. Have fun!

Easy Go problem

How can black win the capturing race and protect the weakness at A?

ggg easy 49 picture

Download the solutions to the easy problem as an SGF or PDF file.

 

Intermediate Go problem

A joseki gone peculiar. Black can live in the corner, but looking after the stones in the center is more important.

ggg intermediate 49 picture

Download the solutions to the intermediate problem as an SGF or PDF file.

 

Hard Go problem

Black can capture white’s group in five moves, but black’s cutting stones only have three liberties…

go problems 49 picture

Download the solutions to the hard problem as an SGF or PDF file.

Still want more Go problems?

You can find Go books packed full of life and death problems, tesuji problems and other valuable Go knowledge at the Go Game Shop.

Discuss other possible moves

If you have any questions or want to discuss any of these problems, please leave a comment below at any time. You can use the coordinates on the problem images to discuss a move or sequence of moves.

You can also download the solutions as a PDF or SGF file by clicking the links below each problem.

About David Ormerod

David likes teaching, learning, playing and writing about the game Go. He's taught hundreds of people to play Go, including many children at schools in Australia. In 2010 David was the Australian representative at the 31st World Amateur Go Championships. He's a 5 dan amateur Go player and is the editor of Go Game Guru. You can find David on Google+ and follow Go Game Guru on Facebook, Google+ or Twitter.

Comments

  1. you should fix the hard problem so it doesnt look like its on the edge of the board

    • David Ormerod says:

      How do you mean? It is on the edge of the board.

      • James Sedgwick says:

        The left side looks like it is on the edge, that confused me also (I couldn’t understand why I hadn’t already solved the problem until I opened the SGF).

        • Yeah, I thought this at first too. Thought I had solved the problem, but nope.

          • David Ormerod says:

            I see, I didn’t realize that. Thanks.

            I’ve changed the problem to remove that illusion. If you’ve already looked at it, you might have to refresh the page or clear your cache to see the new version.

  2. Thanks for the problems David. Like always, the intermediate one is very useful in real games, I think.

    • David Ormerod says:

      No worries Jangalf, it’s supposed to be practical, but it can become surprisingly complex even with the correct first move. I wasn’t expecting that at first :) .

  3. The empty triangle – the key to success!

  4. In intermediate problem there is “correct” variation:
    F3 G2 E2 E1 E3 D1 F1 G1 C1 F1 H3 E5 D6 F5 F6 G3 G4 H4 G5
    But if White continues from that with:
    H2 J3 J2 K3 K2 L3 L2 M2
    He now has 4 liberties and can capture Black corner with B4. That means B can capture W only if 2 Black stones can’t be captured in ladder.

    • David Ormerod says:

      That’s right, so when white starts with H2 in your sequence, black would be better off looking after the corner with black B5, white B6, A4 and making miai of attacking on the left side of the bottom side.

      It doesn’t really matter whether black captures those stones as long as he can manage the overall situation. However, my move at black F6 earlier (while tesuji in some situations) isn’t the best move in this case.

      After white F5, simply extending to D7 or playing G5 looks better. After D7, white still doesn’t have anything better than pushing up with G3, G4, H4, G5, H2, then black C7 gives black an even better result than before.

      I’ll update the solutions for this week, since I need to fix the mirage that the hard problem is in the lower left too.

      • Instead of F6 can’t B play G5 instead? Then it seems as though the sequence runs:

        D7 E6 F6 E7 G6 C7 G3 G4 H4 H5 H2 J3 J2 D7

        catching the two w stones on a large scale, leaving w with a horrible floating group in the centre and a miserable second line burden on the lower side. This seems superior to the simple D7 extension but I could be wrong.

        In my experience B is better off leaving the F1 G1 C1 F1 exchange hanging since the stone at G1 can help w in many circumstances

        • David Ormerod says:

          Yes, G5 works too, but it’s more complicated after white starts trying to setup the ladder again and more difficult to explain. That’s why I originally decided to show F6 instead of G5 when making the solutions.

  5. Claudio ( @Shanguito) says:

    By using google chrome as a browser, the stones seem misplaced. I have the latest java version and its a visualisation problem. Maybe try different browser? Stones look as if they were placed on the empty squares and not intersections. That’s the thing.

    • David Ormerod says:

      That sounds weird Claudio, I haven’t heard about or seen that happen before.

      Could you send us a screenshot when you have time please? Just on twitter would be fine. Thanks for letting me know.

  6. The problems were more about reading one line deeply than imagining unlikely moves, although move 1 is not the most likely in both intermediate and hard.

    I couldn’t do it this week. I clearly have a nudge for shorter creative solutions rahter than these long draws.

    • David Ormerod says:

      I think seeing when to play the empty triangle is a blind spot for a lot of players and because that was the theme this week, it probably made the problems a bit harder than usual. Usually a lot of reading is required to justify that kind of grinding move :) .

      It reminds me of an old game between Cho Hunhyun and Rin Kaiho: http://www.go4go.net/v2/modules/collection/sgfview.php?id=7694 – Rin apparently didn’t imagine that white could play the empty triangle at 54 and after that his game lost its cadence.

      If white uses any other ‘normal’ move to get out, black will be able to extend at N5 and next attach at P5. However, with the empty triangle on the board, I think white would answer N5 with O6. It’s really hard to see! So you’re not alone by any means Dieter.

  7. Leonid Entin says:

    At the end of the correct solution F3E2G2G3H3E5D6F5G5 can’t white win semeai against the black the corner starting with B4?

    • David Ormerod says:

      Yes, white can, but white has had to make black quite thick in the center to gain an approach move at E3 and black can force white to take the corner stones off the board later, so black can still be satisfied. It’s better to play this way than to try to live in the corner.

      Also it’s worth noting that if black had a stone around the top right star point, white’s position would collapse completely.

      In retrospect though, this wasn’t a good position to use as a problem because it’s too unsettled. I wanted something realistic that demonstrated black’s first move, but I should have gone for a more constructed position.

      • Leonid Entin says:

        No, the tesuji is very nice and it’s obvious that Black gains a lot on the outside. I just wonder what is the best order of moves for White. It might be that after initial F3E2G2 it’s better to play B4 before cross-cutting. If now B plays B3B5F1 than W can exchange B1C1 and only now G3H3E5D6F5G5D1. This way W gains a stone at B5 and lessens the number of ko threats in the corner.

        • David Ormerod says:

          Right, it’s really quite complicated because the position is so open. I’m not certain of the ideal move order myself Leonid and it really depends on the trades you’re willing to accept based on the global position.

          Two other things that are worth thinking about though are:

          1. After exchanging B5 for F1, black can also consider giving up D5 to connect under at D1.
          2. White has to play the cut at G3 early enough to ensure it will still be sente. For example, if the white B1, C1 exchange is made before cutting, black will think about answering G3 with E1, which would be quite annoying for white.

          So it does seem to me that it’s necessary to give black more on the outside in order to take the corner stones, if that’s what white wants.

  8. Seems so, B4 B3 A5 gives B a win due to shortage of libs at A6. But B4 B3 B5 leaves B in a pickle. The alternatives to B3 don’t seem to work any better.

  9. What about playing the first move of the hard problem at O7? It looks more natural than either the jump or empty triangle here.

    • David Ormerod says:

      Good questions mafu, O7 is worth considering. In this case, white can answer O7 with a tesuji at N7, which works because of the extra liberty white has at P4.

      After white plays N7, white can answer black O6 with O8 and M7 with M8. I thought I’d added a variation for that, but it looks like I didn’t :) .

Speak your mind