lidraughts.org

Mistakes in puzzles

Hi, today was doing some puzzles and accidentally found alternative solution after which the engine shows even higher evaluation than after the correct solution. The mistake is probably caused by scan because it doesn't see the alternative solution even after first piece is given. The number of the puzzle is 1798, there's a link: lidraughts.org/training/1798

Alternative solution: 2.27-22 18x27 3.33-29 24x22 4.34-30 35x24 5.37-31 26x28 6.38-32 27x47 7.16x29 24x33 8.48-42 47x38

btw. I lost 30 rating points on this one, i don't care that much about puzzles rating so i don't expect any refund but if there is some painless, easy and quick way to give it back to me then i will appreciate.

Hi all,

First of all, again thank you very much for sharing the mistakes. The puzzles below (not all of them, see commentary) will be disabled in a few days!

10x10 draughts:
89 - Incredible that this one has been found so late
908
1686
1798 - Actually a beautiful alternative solution!!
2504
3701
5656

Frisian draughts:
257
268

Russian draughts:
150
358 - No - The suggested 3. e3-d4 isn't winning because of g5:a3, so puzzle is correct
399 - No - You already found this was false alarm :)

Regards

@apieti this is "give 3, take 3" shot which results in getting a king, but if you avoid sacrifice 24-30, your king is going to be trapped immediately by 40-34, and you get no advantage

@HawaiiBlue capture with the king should be done to field 2 instead of field 49, then its winning. Correct solution probably entered wrong.

Not a mistake but in puzzle lidraughts.org/training/4299 I would like to see black react with 20. ... 19-23 instead of giving away a piece with 20-24. I understand 20-24 is the response from a computer, it is objectively the best move.
In the spirit of it being a puzzle the response 20. ... 19-23 21. 44-40 (30-24?) 23x34 22. 40x29 4-10 would be better. Now white has several moves that win (a piece): A 30-24 10-15 39-34/42-38, B 39-33 10-15 42-38, and C 39-34 and D 26-21 30-24 are probably also winning.
The best line I see for the puzzle is 33-29x29x29 19-23 44-40x29 4-10 30-24 10-15 42-38 18-23 29x18 20x29 27-21 16x27 32x21 12x23 21x1.

Reconnecting