Stockfish can now win KRK ending?

[Jouni]

Latest prerelease can mate with rook :

Using ./stockfish_fix1 on KRvK_1000pv.epd with --nodes 10000000 --mate 0
Engine ID: Stockfish dev-20260505-1429d98e
Total FENs: 1000
Found mates: 1000

[towforce]

Checkmating a lone king with a rook is easy. Are you saying the current version of Stockfish cannot do that? That doesn't make sense!

[Paloma]

Current dev version: 20260517-f8aa78e0
Previously:
dev-20260510-dd321af5
So is dev-20260505 somewhat older

[peter]

There wasn't any 260505 at site of (pre)releases

https://github.com/official-stockfish/S ... h/releases

, 260504 was followed by 260510, regards

[Eelco de Groot]

Checkmating a lone king with a rook is easy. Are you saying the current version of Stockfish cannot do that? That doesn't make sense!

To provide some context for even more lazy or clueless people than we , simply Googling Jouni's text; It had, at least according to the developers something to do with aging of hashtable entries, secondary aging was thrown out and that did not mix totally with latest tunes and extensions. So the aging was reintroduced. Of course the tests are with low search depths or in this case limited nodes. I am just glancing over this reported SF issue, probably more on Discord: https://github.com/official-stockfish/S ... ssues/6742


Last entries on GitHub read:

A recent test event at TCEC had Reckless up against SF15-1G (fixed nodes player), and perhaps remarkably SF15-1G appeared to show considerably better "matefinding" ability than Reckless did despite a considerable time advantage to Reckless: https://tcec-chess.com/#div=fdts&game=3&season=29

Ciecke also commented "phrax has started doing the same thing after recent extension patches and vltc tunes"

vondele
added a commit that references this issue 14 hours ago

Reintroduce Secondary TT Aging
94beadf

vondele
closed this as completedin 94beadf14 hours ago

[syzygy]

Latest prerelease can mate with rook :

That's one small step for mankind, one giant leap for Stockfish.

[towforce]

Checkmating a lone king with a rook is easy. Are you saying the current version of Stockfish cannot do that? That doesn't make sense!

To provide some context for even more lazy or clueless people than we , simply Googling Jouni's text; It had, at least according to the developers something to do with aging of hashtable entries, secondary aging was thrown out and that did not mix totally with latest tunes and extensions. So the aging was reintroduced. Of course the tests are with low search depths or in this case limited nodes. I am just glancing over this reported SF issue, probably more on Discord: https://github.com/official-stockfish/S ... ssues/6742


Last entries on GitHub read:

A recent test event at TCEC had Reckless up against SF15-1G (fixed nodes player), and perhaps remarkably SF15-1G appeared to show considerably better "matefinding" ability than Reckless did despite a considerable time advantage to Reckless: https://tcec-chess.com/#div=fdts&game=3&season=29

Ciecke also commented "phrax has started doing the same thing after recent extension patches and vltc tunes"

vondele
added a commit that references this issue 14 hours ago

Reintroduce Secondary TT Aging
94beadf

vondele
closed this as completedin 94beadf14 hours ago

Thank you - that was helpful. I had assumed that I'd misunderstood something, or that something had been mistyped - but yes - I could have searched.