I think that’s because black could respond with F18 which both blocks white from connecting to the right and removes one white’s liberty.
Thanks to the exchange H19+G18, E19 increases white’s liberties in sente.
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Yes, that preliminary exchange is magic, black can only connect first, everything else doesn’t work, and after white sagari, black can only forbid the white connection without being able to put away a lib of white. Awesome. And yes I agree F18 Works for b if white doesn’t Atari before
@Starline & @“others”.
As Starline mentioned, there are several move modes:
What kind of move mode do you prefer for player and opponent?
Player: What kind of move mode do you prefer?
- Free placement
- Only preprogrammed variations
- No preference
0 voters
Opponent: What kind of move mode do you prefer?
- Opponents moves played by computer.
- Manually (I play both Black and White).
- No preference.
0 voters
This puzzle is from @mark5000’s Exercises for Beginners collection.
Doing a few puzzle a day is a good way to improve your skills and achieve a higher rank.
White to move and kill Black.
This puzzle is ranked: 16 kyu.
Interactive Puzzle
White is to connect his two groups.
White to move.
Interactive Puzzle
Good luck and have a nice day.
2 Likes
Puzzle 72 Maeda Nabuaki. For me some wrong answers seem not wrong (less optimal maybe but still working)
Instead of Q19, P16 or P17 working too
I give the solutions of the puzzles as they were presented by the author.
Not impossible that there are other solutions.
Program defines anything else as wrong 
With about 1900 puzzles it would take me a lifetime to provide all different paths for all puzzles. And since I am a lazy person I will not do so.
I hope that I will finish checking “my” puzzles this year and also providing descriptions and an approximately correct rankings.
By then it will have be all and all a three months project (and there comes a time for other projects).
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Well it’s then confusing to call wrong something working… I spent quite some time to check and check again, not seeing why I am wrong. If there are more solutions as one, they should definitely be labeled correct
See my previous (edited) post.
I suppose if there seems to be valid alternate solutions @Atorrante could just wait until they’re flagged and add them in, as opposed to trying to anticipate all the possible correct incorrect paths, which would be too much work.
That way at least popular puzzles or ones people feel strong enough about get a little more attention 
Yeah I think it’s the way the OGS puzzles work. If you don’t label it as correct and it hits the end of a tree or there’s a move that isn’t in the tree, it’s just auto-labelled as wrong by default.
1 Like
Well I dunno, no offense intended, I just noticed something wrong in that puzzle, besides I did a few more problems without anything to say. Maybe it’s just a scribing miss?
I’m not asking all 1900 to be reviewed by 1 benevolent, I just hope that if someone point something strange, it could be edited in whatever way.
I know nothing about how the OGS puzzles editing works, but it would be a bit of pity if you can’t have more as one correct answer. But I would more expect a writing failure here, as it’s always surprising and doubtful in this kind of books to get that multiple answers.
no offense taken.
I know what you mean from looking at that puzzle now. Do you think it’s something to do with the number of potential ko threats you get from the position?
Black should get sente in both cases. In the correct answer I think there’s two ko threats. Capturing the one stone with p19, and then playing t18 to force the capture.
Playing P17 or P16 works for capturing, but then t18 should still be a threat, then say you answer with the other one of P16/P17 then connecting T16 is a threat, and finally T19 as a third threat. So that’s three threats.
If you instead answer t18 with say Q19, then I think P19 throw in is a threat. I think you answer with the other move P16/P17, and then finally R19 capture as the third threat again. So still three ko threats (possibly four if you captured the throw in stone I think )
Does that seem plausible as to if it could be less optimal?
1 Like
Yep sure. I still think there could just be a reproducing mistake, because I didn’t have that kind of different solutions and impression in the other problems I did in this collection. After the sagari played, looks like all is working, which gives many branches and is quite uncharacteristic of a life and death problem.
2 Likes
December 5 is a special day in the Netherlands: Sinterklaas.
You can read about in this wikipedia post.
Bottomline: all good children get presents.
Assuming that you all behaved very well this year, you will get an extra go puzzle.
And here they are.
Black to start and live.
Interactive Puzzle
Black to start.
Interactive Puzzle
Black to start and connect his two groups.
Interactive Puzzle
Black to move and play some surprising moves.
Interactive Puzzle
White to live in the corner.
Interactive
Black invades the White group and kills it from the inside.
Interactive
I have two questions.
Edit: actually three. 
-
When I click the link I always find the puzzle in a different combination of colours and orientation. I think I have disabled all buttons in my ui, so maybe you have them activated?
-
Spoiler
- About the other puzzle
click
Is that dead?
It looks seki to me
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Spoiler
S19 R19 T16 S15 S14 
Edit: No, this doesn’t work, I thought white had a stone on Q19…
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This has been puzzling me too. You are probably right about me having them activated.
It will keep you flexible
1 Like
What if black extends S15?