when the spring comes (NEW 2v16 LENGTH RECORD ?!)

[Hobacle]

But we ought to get its exact DTM, because it may be an earthshaking record of KPv16.

Too long for an exact DTM by Backward with game playing engine.

Best so far ist SF MOJO with unchecked Null Move pruning.
Even maybe 20 moves shorter then I had thought before?

[pgn][Event "?"]
[Site "?"]
[Date "2021.10.01"]
[Round "?"]
[White "Hobacle, Spring"]
[Black "16, 2"]
[Result "*"]
[SetUp "1"]
[FEN "8/4p2p/7p/4pp1k/8/5pp1/P2Kprrb/4nbqn w - - 0 1"]
[PlyCount "61"]

1. Kxe1 Kg6 2. a4 h5 3. a5 h4 4. a6 h5 5. a7 h3 6. a8=Q Kg5 7. Qg8+ Kh6 8. Qf8+
Kg6 9. Qd8 Kh6 10. Qg8 e4 11. Qf7 e3 12. Qg8 h4 13. Qf7 Kg5 14. Qg7+ Kh5 15.
Qh7+ Kg5 16. Qf7 f4 17. Qe6 Kh5 18. Qg8 Kh6 19. Qg4 Kh7 20. Qg5 e6 21. Qg4 e5
22. Qg5 Kh8 23. Qg6 e4 24. Qh6+ Kg8 25. Qf6 Kh7 26. Qf8 Kg6 27. Qe7 Kf5 28. Qd6
Kg5 29. Qe6 Kh5 30. Qf6 Kg4 31. Qg6# *
[/pgn]

4...h5?! is probably a mistake.
The possible mate at g4 is what I was worried about indeed.

[peter]

for those who want to experiment...Chest could be a good help here...just an example so far, more to come hopefully later...i take the initial position for which Paloma gave the Diagram:
[d]7k/4p3/4p3/8/8/5pp1/P2Kprrb/4nbqn w - - 0 1
after 1.Kxe1 !! e5 ?, Chest gives a mate within around 4 sec with these parameters (pretty sure that PieceLimit and MaxMoves are perfectly chosen):
ChestUci-parameters:
<
HashSize: 2048 mb
ProblemType: mate
SearchDepth: 128
SearchMode: special
ChecksOnly: 14
KingSquares: 9 (or 0, that makes no difference)
PieceLimit: 3
MaxMoves: 11

everything else on default
>
have a try on your own and u will see

Well, yes, Peer, but as we saw (if we aren't both wrong, Hobacle and me) moving the black e-pawn unforced is the basis to White's win in original position at all. And if there's more pawns added, as Hobacle's intention for KPv16 is nowadays, Chest's P3 doesn't work anymore.
I'm outa here for the moment regards

[peter]

4...h5?! is probably a mistake.

Yes, as well as 3...h4 and especially 5...h3, here at least some mate- score in output, even if now probably somewhat too long:


[fen]8/4p2p/7p/4pp1k/8/5pp1/P2Kprrb/4nbqn w - - 0 1[/fen]


Analysis by Stockfish-MOJO 020521:

1.Kxe1 Kg5 2.a4 Kg6 3.a5 h5 4.a6 Kg5 5.a7 Kf6 6.a8Q Kf7 7.Qd8 Kf6 8.Qh8+ Kg6 9.Qg8+ Kh6 10.Qf7 Kg5 11.Qxh7 Kg4 12.Qg6+ Kf4 13.Qxh5 Ke4 14.Qe8 Kd5 15.Qb5+ Kd6 16.Qc4 Kd7 17.Qc5 Ke6 18.Qc6+ Kf7 19.Qa6 Kg7 20.Qe6 f4 21.Qa6 Kf7 22.Qc6 Kg8 23.Qc4+ Kf8 24.Qb3 Ke8 25.Qe6 Kd8 26.Qc6 e4 27.Qb7 Ke8 28.Qc8+ Kf7 29.Qf5+ Kg8 30.Qxf4 Kg7 31.Qf5 Kg8 32.Qd5+ Kf8 33.Qc4 Ke8 34.Qe6 Kf8 35.Qg6 e3 36.Qf5+ Kg8 37.Qd5+ Kf8 38.Qc4 Ke8 39.Qe6 Kd8
+- (#79) Depth: 67/84 00:02:47 15015MN

[Hobacle]

for those who want to experiment...Chest could be a good help here...just an example so far, more to come hopefully later...i take the initial position for which Paloma gave the Diagram:
[d]7k/4p3/4p3/8/8/5pp1/P2Kprrb/4nbqn w - - 0 1
after 1.Kxe1 !! e5 ?, Chest gives a mate within around 4 sec with these parameters (pretty sure that PieceLimit and MaxMoves are perfectly chosen):
ChestUci-parameters:
<
HashSize: 2048 mb
ProblemType: mate
SearchDepth: 128
SearchMode: special
ChecksOnly: 14
KingSquares: 9 (or 0, that makes no difference)
PieceLimit: 3
MaxMoves: 11

everything else on default
>
have a try on your own and u will see

Three hours passed without any results on my computer.

[Spliffjiffer]

after 1.Kxe1 !! e5 ?

if 3h passed away then i must relook the parameters i gave (10 sec at max)...ill give an update after my search has running through...currently i check with Chest with PL=3 and MaxMoves=11 and SearchMode=special with search depth=60...im at SearchDepth 59 atm, the engine searches since about 12 hours...plz wait it up

addition(edited):
i know that 1...e5 gives mate in 55 after 4 sec but im currently not able to have a research...maybe someone else can confirm this atm, thx !

[peter]

Try this: 8/4p3/8/4p2k/8/5pp1/P2Kprrb/4nbqn w - - 0 1
Then we can add other pawns gradually.

Even if we did that already in the meantime too (added the other pawns), here's the position with 2vs13 and pawns at e7, e5:


[fen]8/4p3/8/4p2k/8/5pp1/P2Kprrb/4nbqn w - - 0 1[/fen]

Analysis by Stockfish-MOJO 020521:

1.Kxe1 Kg4 2.a4 Kf5 3.a5 Kf4 4.a6 Ke4 5.a7 Kd5 6.a8Q+ Kc4 7.Qb7 Kd4 8.Qb4+ Kd5 9.Qa4 Kc5 10.Qe4 Kb5 11.Qc2 Kb4 12.Qc6 Kb3 13.Qc5 Kb2 14.Qc4 e6 15.Qc5 Kb3 16.Qc7 Kb4 17.Qc2 Kb5 18.Qc3 Kb6 19.Qb4+ Kc6 20.Qa5 Kd6 21.Qb5 Kc7 22.Qa6 e4 23.Qb5 Kd6 24.Qc4 Ke5 25.Qc5+ Kf6 26.Qc7 Kf5 27.Qd6 Kf6 28.Qc5 Kf7 29.Qg5 Kf8 30.Qf6+ Ke8 31.Qg7 Kd8 32.Qb7 e3 33.Qc6 Ke7 34.Qc7+ Kf6 35.Qf4+ Kg7 36.Qg5+ Kf8 37.Qd8+ Kf7 38.Qh8 Ke7 39.Qd4 e5 40.Qd3 Ke8 41.Qh7 Kd8 42.Qb7 e4 43.Qf7 Kc8 44.Qa7 Kd8 45.Qb7 Ke8 46.Qc7 Kf8 47.Qd7 Kg8 48.Qe7 Kh8 49.Qe5+ Kh7
+- (#66) Depth: 88/102 00:06:22 30171MN


Not so much shorter then the corresponding one with 3 pawns more, so this complete one's DTM will be about right maybe too.

forum3/viewtopic.php?p=907443&sid=3ab74 ... f5#p907443

Hope, it's (#78 or so) yet a record quaking enough for you anyhow

[Hobacle]

after 1.Kxe1 !! e5 ?

if 3h passed away then i must relook the parameters i gave (10 sec at max)...ill give an update after my search has running through...currently i check with Chest with PL=3 and MaxMoves=11 and SearchMode=special with search depth=60...im at SearchDepth 59 atm, the engine searches since about 12 hours...plz wait it up

Just because my hardware is too weak. If my hashtable size can be 64GB, maybe I'll be able to get the exact DTM by SF11 only...

[Hobacle]

Try this: 8/4p3/8/4p2k/8/5pp1/P2Kprrb/4nbqn w - - 0 1
Then we can add other pawns gradually.

Even if we did that already in the meantime too (added the other pawns), here's the position with 2vs13 and pawns at e7, e5:


[fen]8/4p3/8/4p2k/8/5pp1/P2Kprrb/4nbqn w - - 0 1[/fen]

Analysis by Stockfish-MOJO 020521:

1.Kxe1 Kg4 2.a4 Kf5 3.a5 Kf4 4.a6 Ke4 5.a7 Kd5 6.a8Q+ Kc4 7.Qb7 Kd4 8.Qb4+ Kd5 9.Qa4 Kc5 10.Qe4 Kb5 11.Qc2 Kb4 12.Qc6 Kb3 13.Qc5 Kb2 14.Qc4 e6 15.Qc5 Kb3 16.Qc7 Kb4 17.Qc2 Kb5 18.Qc3 Kb6 19.Qb4+ Kc6 20.Qa5 Kd6 21.Qb5 Kc7 22.Qa6 e4 23.Qb5 Kd6 24.Qc4 Ke5 25.Qc5+ Kf6 26.Qc7 Kf5 27.Qd6 Kf6 28.Qc5 Kf7 29.Qg5 Kf8 30.Qf6+ Ke8 31.Qg7 Kd8 32.Qb7 e3 33.Qc6 Ke7 34.Qc7+ Kf6 35.Qf4+ Kg7 36.Qg5+ Kf8 37.Qd8+ Kf7 38.Qh8 Ke7 39.Qd4 e5 40.Qd3 Ke8 41.Qh7 Kd8 42.Qb7 e4 43.Qf7 Kc8 44.Qa7 Kd8 45.Qb7 Ke8 46.Qc7 Kf8 47.Qd7 Kg8 48.Qe7 Kh8 49.Qe5+ Kh7
+- (#66) Depth: 88/102 00:06:22 30171MN


Not so much shorter then the corresponding one with 3 pawns more, so this complete one's DTM will be about right maybe too.

forum3/viewtopic.php?p=907443&sid=3ab74 ... f5#p907443

Hope, it's (#78 or so) yet a record quaking enough for you anyhow

Are you sure about the DTM?
In fact #50 is enough, because the original record of KP(rank2)v16 is #16 (from SuperProblem.ru).

[peter]

Are you sure about the DTM?

As for KPvs13 more or less yes, about KPvs16 not quite, maybe tomorrow

[Hobacle]

Are you sure about the DTM?

As for KPvs13 more or less yes, about KPvs16 not quite, maybe tomorrow

Quite thanks for your help, but please make it sure as soon as possible, because there's not much time for me any longer, just five hours!
Here was my personal record for KPv16 (before today) :
[pgn][Event ""]
[Site ""]
[Date ""]
[Round ""]
[White ""]
[Black ""]
[Result ""]
[SetUp "1"]
[FEN "7k/4pp2/6p1/8/8/6p1/PKp1pprp/2nbrqbn w - - 0 1"]
[PlyCount "83"]

1. Kxc1 Kg7 2. a4 Kh8 3. a5 Kg8 4. a6 Kg7 5. a7 Kf6 6.
a8=Q Kf5 7. Qh8 Ke6 8. Qg7 g5 9. Qxg5 Kd6 10. Qf5 f6 11. Qc8 Ke5 12. Qg4 f5 13.
Qg7+ Ke6 14. Qd4 f4 15. Qxf4 Kd5 16. Qf7+ Kd6 17. Qf5 e6 18. Qg5 Kc6 19. Qd8
Kc5 20. Qd7 e5 21. Qd3 Kc6 22. Qd8 Kc5 23. Qd7 Kb6 24. Qd6+ Kb7 25. Qxe5 Ka7
26. Qe8 Kb7 27. Qd8 Kc6 28. Qe7 Kd5 29. Qd7+ Kc5 30. Qe6 Kd4 31. Qd6+ Kc4 32.
Qe5 Kd3 33. Qd5+ Ke3 34. Qc4 Kf3 35. Qc6+ Ke3 36. Qd5 Kf4 37. Qe6 Kf3 38. Qe5
Kg4 39. Qf6 Kh5 40. Qg7 Kh4 41. Qg6 Kh3 42. Qh5# *[/pgn]

All of my 2v16 records had been ready several days ago, but later I found our new theme for KPv16. Although today's work seems valuable, I don't want to delay the release.