Groin¹ in books corner 📚

I’m still a DDK at heart :sweat_smile: (last rank adjustment promoted me to SDK) so here’s my try

endgame problem

I think there’s 4 different moves to consider the order and sente or gote, ABCD:

I think that A must be the first move for black, it’s sente because the follow up is so big (destroy whites upper left territory) I didn’t count what happens if white ignores this

GBC- 2 yose for ddk A

After that I just tried to count the remaining moves, to compare the score.

First, B if black plays first:

GBC- 2 yose for ddk B1

if white plays first:

GBC- 2 yose for ddk B2

Assuming these basic variations (assuming opponent responds and doesn’t ignore) it seems like +2 points territory +1 point for capture for whoever goes first. Does this mean that it’s effectively a 6 point swing? This is where I start to get confused… Also confused about what happens if the opponent doesn’t respond here, it seems like there’s another 1 point for reduction

Okay moving on to C, if white plays first:

GBC- 2 yose for ddk C1

This looks like it’s worth +2 points territory +2 points captures for white

But if black plays first, it’s just +0 points, just preventing white from getting +4

GBC- 2 yose for ddk C2

Last one, D if black plays first:

GBC- 2 yose for ddk D1

So +2 points for black, If white goes first I think it’s basically preventing black from getting those points:

GBC- 2 yose for ddk D2

Black could also turn at C1 in gote to reduce 1 white point…

Okay here’s my summary of the value between BCD:

  • B - 6 points (1 extra for reduction?)
  • C - 4 points
  • D - 2 points (1 extra for reduction?)

But what gets really confusing to me is which of these is really sente or gote, because it seems like the best play is actually to ignore sometimes (in other words is not actually sente)?

Here was my final sequence:

1-4 Black starts here because it’s so big, and ends with sente
5 Black plays here for +3 points
6 White ignores because this is worth +4 and follow up to Black 5 is only 1??
7 Black does not follow up because this is worth +2??
8-9 White can play here in sente, and Black responds to keep the points??
10 White finishes here

I’m very much not confident in this evaluation or ordering, so won’t bother counting final score yet…

Just my humble opinion, the other problems are not that easy I think, for new ranks DDK… at least this new ranks 8k has a hard time :sweat: this is the only one I have a bit of confidence in:

lower right

Black to connect to friends

Fun topic though :+1:

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@michiakig

Endgame problem

If Black A9 is followed by White A10 then Black double ataris with B10.
And also, Black can play move 7 at C1.

Lower right

What if White plays 4 at 5?

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A few more detailed answers:

Endgame problem

Michiakig was correct about the order of moves. The size of B is not easy to compute because of the possible followup but we can see that it’s at least a 6 point swing, so is bigger than C anyway so there is no need to make a precise calculation. Black wins by 0.5.

Problem 2, upper right corner

problem2-2

Problem 2, lower right corner

A hint on problem 2, lower left, in case someone wants to look at it and didn't succeed so far

Assuming I didn’t misread of course: find a move that allows to save either D4 or H7

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There is better play for upper right

This?

problem2.2

Let see. What if white answers 1 at M18 ?

Black's followup

Racoon’s belly tesuji?
racoon

You can atari and then block if w connects. Both white piece of stones are then lacking of liberties.

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So the lower left is still not solved and It’s a call to DDK’s as in my opinion it is the easiest of all.

I vote for “A brilliant move in a pro game”

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here’s my try for lower right again, thanks jlt for the hint:

lower right

black to give up 2 stones to connect?
Screenshot 2021-11-17 at 08-26-18 GBC- 2 Problems for DDK

Lower left, I thought I solved in my head but after trying the board realized I had misread :sweat:

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Alll I am saying is you got the upper left wrong. You variation can be resulted in ko.

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I solved them all, but I don’t think I should share as I am a bit overlevel. Also, I meant you should share it here if you come across four kos game.

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Here is the book from which i extracted the very first problems (the yose is the second one in the book)

Here are the answers


My solution to the upper left problem is diagram 3 of my post (I said that diagram 1 was my first wrong attempt), and it is the same as the solution of the book. Only moves 2 and 4 are interchanged but I think it doesn’t matter.

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Yes, I didn’t see your third diagram. Sorry.

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You should probably post about joseki commonly played in pros’ games and recommened by Ai. Would be good for the beginners and intermediate players to know which joseki they should play. I think the fact that there are hundreds of joseki variations is quite dauting for beginners. Little did they know that there are only a few of those hundreds that are actually used.

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GBC- 3

Black to play

Level: dan and up.

Sandbox

So a middle game problem from a game between Sakata Eio (Black) and Fujisawa Hideyuki (White)

White’s intention is to attack the black stones in the upper right corner while taking into account that the center is not very stable.

With one arrow, white is using three of his groups.

So, in the face of white’s attack, how Black will respond skillfully?

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No dan player wants to try? I really want to play at N14 but the continuation looks complicated.

It’s not exclusively for dan players , so any research of yours are welcome too. Maybe it could give incentive for help from strongers anyway.
Btw your first move looks interesting