Weekly Go problems: Week 117

Here are the weekly Go problems for week 117.

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

Easy Go problem

This sort of situation comes up fairly often in the corner. Black can make two eyes with one move.

ggg easy 117 picture

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

 

Intermediate Go problem

White seems to have a lot of eyespace, but her shape is short of liberties.

ggg intermediate 117 picture

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

 

Hard Go problem

This problem looks almost the same as the previous one, but has different strengths and weaknesses. Be careful about relying too heavily on memorized sequences, as they can lead to blunders when the situation is a bit different.

go problems 117 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. The intermediate one wasn’t standard for me. It was even a challenge not to solve by trial and error. The first move looks obvious but it is not easy to prove that the basic moves (reducing space) are wrong. From that exercise, a pattern emerges though.

    The hard one was hard. I needed to click and try.

    • Younggil An says:

      You’re right. Intermediate one is not that hard, because there aren’t many possible variations if your first move is correct. However, hard one is pretty hard. :)

      • I had a hard time solving the intermediate one, although I was very close to solving it the first time but didn’t see one of the moves. I ended up finding it by trial and error. However, I easily solved to hard problem on my first try. I was pretty much going on instinct, but it worked!

    • David Ormerod says:

      That’s interesting Dieter,

      The intermediate problem is a standard corner shape for me, so I made an assumption (possibly incorrectly) that other players would recognize it too and then compare it to the hard problem. I’m too much of a Go problems nerd, I guess :)

      • In the meantime I found they are successive problems in a standard collection. If you have gone through those in your career, indeed such problems become familiar, especially the solid one (intermediate) which itself has some relationship to the big L-group.

        • David Ormerod says:

          Yes the intermediate problem comes up a lot in various collections and variations on standard corner shapes (like the big L-group).

          I haven’t seen the hard problem that often, but it does appear in one of the classic collections (I think it’s the Guanzi Pu).

          I remember it whenever I see the more basic variant, because it always astonishes me how just removing one stones creates a completely different (often more difficult) problem.

  2. jangalf says:

    Thanks for the problems David. very intresting ones.

    • David Ormerod says:

      Thanks jangalf, I’m glad to hear you enjoyed them. I’m looking forward to posting the problems each week again now, like we used to.

  3. Dunno. As usual, the intermediate one seems harder to me. I solved the hard one on the first try, and I had to look at the solution on the intermediate.

    • David Ormerod says:

      That’s really interesting pasko. For me it’s the complete opposite. I guess that’s why even pros sometimes don’t expect one another’s moves.

  4. Charlie H (2D) says:

    An odd box for me this time, the intermediate one is a standard shape, but one I never learned correctly, so I spent a long time on it figuring out all the possiblities.
    The hard one I did very quickly, but that was by luck because there were loads of variations I didn’t consider. I then had a very educational session of going through the variations i hadn’t thought of :).
    Nice problems, as always.

    • David Ormerod says:

      I was surprised by the number of variations in the hard problem too Charlie.

      Usually when you choose a problem, you have a feeling for approximately how hard it is. However, sometimes it’s not until you start to consider all the other variations that people might try that you realize just how complicated things can get.

      One thing about Go that never ceases to amaze me is just how much can happen in a 5×5 corner position.

  5. Well, I found the hard one harder – the intermediate one just looked like a one tesuji trick after other moves discounted. There is more than one route to ko in the hard one, it took me longer to look at all the paths and solve it thoroughly.

    Now How about the “trick move” by Ida in the 69th honinbo game 3 (large knight slide in the upper right) – I’d love to see a problem based on that one! :-)

  6. Or perhaps I should try and compose one myself? :-*

  7. In the intermediate problem: What is the reason of White 6? Or to ask it a bit different: Why didn’t white put the stone in the middle of the three black stones (e.g the place that Black 7 uses)?

    • Younggil An says:

      That’s a good question Daniel.
      If White plays at 7 instead of 6 in your variation, Black can atari under at R1, and White can’t do anything because her three stones are in atari. If you still can’t see that, feel free to let us know. :)

  8. Black R1, White T2 (remove black T3) –> Black must react with S1 (otherwise White can play R4 and has three eyes).
    Black cannot play R4 or T3 (illegal moves), cannot play T1 (White Q1) except if he first plays Q1.
    Black needs now 4 moves to kill white.
    White P3 needs Black P2 (otherwise black Q2/Q3 are dead).
    This now leads to a ladder right into the center of the board (without any other stones, black will win and then white is dead. So much I agree). But white IMO has the advantage of initiative.

    With the proposed moves, after Black T1, White R1, Black T6 –> White is dead (If white not R1, than Black R1 –> White is dead too). So IMO this is definitely worse for white.

    But then, maybe I missed something…

    • Younggil An says:

      Thanks Daniel for your detailed explanation, but it’s a bit confusing to me.
      There might be some other possibilities, but since it’s a life and death problem, you don’t have to care too much about the outside unless it’s not solid enough to seal White in.

      Anyway, thanks a lot for your effort and time to share your opinion, and I’m sorry that this comment area is not good enough to talk about the sequence clearly.
      We’re going to upgrade this comment box to put some variations, then it’ll help us to talk about the complicated variations.
      Thanks. :)

  9. Just a side note: I’m by far no GO expert (only a couple of weeks into the game myself…). So the main point was: Maybe I overlooked something crucial where White S3 will lead to a quick defeat.

    But currently I still think that White S3 will provide a much better position for White in the long run. Black can still beat white in the long run if no other stones are on the board (which we can assume in this “Life or Death” problem). However it needs quite a few moves more (Black needs to secure Q2 and Q3 because Otherwise White can easily surround them within 4 moves.

    “Life or Death” problems IMO should be about using the moves that force the opponent to react (or if he doesn’t, then he’ll just loose faster/more). So If white survives longer and makes it harder for black to force it, IMO it should be the “preferred” move. (Note: I’m still not sure it actually IS the better move…)

  10. Just to notify: I’ve found a mistake in my reasoning now…
    After White P3, Black should play O3 (and not P2). This will kill the attack of White and while black still needs 4 moves to effectively kill the white corner, white doesn’t have any counter anymore…

    (Maybe the wording of the previous comment is a bit misleading: The point is, that I’m trying to learn about the game by figuring out WHY somebody plays a certain stone. Sometimes I look at a move and just see no reason for it… usually because I overlook something)

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