1.g4 opening is losing?

[zullil]

Too many possibilities to prove it but what could be feasible is to test all white responses within let's say 0.2 pawns off the main SF and LC0 line (more lines closer to the root) down to >3.0 eval at decent time controls. This would pretty strongly suggest that it's lost. You could start at just 0.1 and 2.0 and make it a distributed project. Same with some other opening lines. You could also try to get an actual estimate of the likelihood that 1. g4 is lost with perfect play but that's for another post.

Here's something to bear in mind:

[d]8/6pk/7r/8/8/7P/6QP/7K w - - 0 1

Without 7-man endgame tables, Stockfish-dev's (static) evaluattion of this position is +4.67. But it's a draw. How many similar positions are there, say with eight or nine men, that Stockfish totally misevaluates?

So in the middlegame, when Stockfish is searching at selfdepth 80, it's making choices that are influenced by completely erroneous leaf evaluations.

What if the only way to draw with 1. g4 is to head for such a position? Will Stockfish find it?

The static evaluations of current engines in endgame positions (not covered by tablebases) is very very far from perfect. And if they can't correctly evaluate endgames, they can't evaluate certain earlier positions either.

Code: Select all

./stockfish 
Stockfish 060220 64 BMI2 by T. Romstad, M. Costalba, J. Kiiski, G. Linscott
position fen 8/6pk/7r/8/8/7P/6QP/7K w - - 0 1
d

 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   | p | k |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   | r |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   |   |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   | P |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   | Q | P |
 +---+---+---+---+---+---+---+---+
 |   |   |   |   |   |   |   | K |
 +---+---+---+---+---+---+---+---+

Fen: 8/6pk/7r/8/8/7P/6QP/7K w - - 0 1
Key: 03735D4FB6B3B187
Checkers: 
eval
     Term    |    White    |    Black    |    Total   
             |   MG    EG  |   MG    EG  |   MG    EG 
 ------------+-------------+-------------+------------
    Material |  ----  ---- |  ----  ---- |  6.47  6.61
   Imbalance |  ----  ---- |  ----  ---- |  0.19  0.19
       Pawns | -0.22 -0.66 | -0.08 -0.20 | -0.14 -0.46
     Knights |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
     Bishops |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
       Rooks |  0.00  0.00 |  0.10  0.02 | -0.10 -0.02
      Queens |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
    Mobility |  0.41  0.67 |  0.15  0.73 |  0.26 -0.06
 King safety | -0.42 -0.05 | -2.01 -0.40 |  1.59  0.35
     Threats |  0.10  0.10 |  0.42  0.42 | -0.32 -0.32
      Passed |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
       Space |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
  Initiative |  ----  ---- |  ----  ---- | -0.58 -0.82
 ------------+-------------+-------------+------------
       Total |  ----  ---- |  ----  ---- |  7.38  5.48

Total evaluation: 4.67 (white side)

[Spliffjiffer]

yes, exactely @ Louis

or even worse if you like:
[d]b4bN1/4p1p1/1Q1p2K1/q1np4/3p1Rnk/6pr/4Rppr/3N4 w - - 0 1
mentioned by Corbit afaic remember
i gave SF11 15 min with 4 cores+TB and it shows 1.Qxa5 with a score of about -46...time to resign, isnt it?
well you unmisunderstandably sense the irorny

and as sayed, there are countless of such positions oc

[Ovyron]

The static evaluations of current engines in endgame positions (not covered by tablebases) is very very far from perfect.

But, does that matter? Because an user wouldn't just take Stockfish's eval as gospel and play the highest scoring move, they'd check if the engine can still produce moves that lead to a won position from that score. The winning player is expected to have a line that goes up to a won position (and I mean a won position, not one with high score) and then if the other side can't avoid reaching it or the avoidance leads to other won positions, we know it's won without needing to prove it.

We don't care about what eval Stockfish gives to the moves because the user has other ways to check if the positions are won, they can be won as low as -1.8 eval so if the user knows it they'd rather reach this position than a 3.00 one where the result is unknown.

[jp]

The static evaluations of current engines in endgame positions (not covered by tablebases) is very very far from perfect.

But, does that matter? Because a user wouldn't just take Stockfish's eval as gospel and play the highest scoring move, they'd check if the engine can still produce moves that lead to a won position from that score.

It only doesn't matter if the halves of a centaur complement each other so well that the centaur is perfect, but there is no centaur that is anywhere near perfection.

[Ovyron]

It only doesn't matter if the halves of a centaur complement each other so well that the centaur is perfect, but there is no centaur that is anywhere near perfection.

You don't need perfection to win won positions, you'd only need it if 1.g4 was drawn and to win you need to make perfect moves that cause the defending player to trip. If 1.g4 loses black can take the luxury of playing the worst move that keeps the win and still win, no best move necessary.

[jp]

You don't need perfection to win won positions,

It depends how difficult the theoretical win (or draw) is.

The real point isn't about perfection, but that centaurs are nowhere near good enough to be able to say that the weaknesses of computers don't matter.

[zullil]

You don't need perfection to win won positions,

It depends how difficult the theoretical win (or draw) is.

Right. Is there a handy example of a 7-man position that is a theoretical draw for the side to move, but for which only one or two non-obvious moves hold the draw? Imagine how many such positions there would be with 8 men. Or 11 men.

[jp]

Right. Is there a handy example of a 7-man position that is a theoretical draw for the side to move, but for which only one or two non-obvious moves hold the draw?

I'm interested in finding such positions too, e.g. the simplest possible endgame positions that are too hard for computers alone or even centaurs. They'd probably need to be at least 5-man, I guess.

[zullil]

Right. Is there a handy example of a 7-man position that is a theoretical draw for the side to move, but for which only one or two non-obvious moves hold the draw?

I'm interested in finding such positions too, e.g. the simplest possible endgame positions that are too hard for computers alone or even centaurs. They'd probably need to be at least 5-man, I guess.

[d]6N1/3n4/3k1b2/8/1r6/5K1Q/8/8 w - - 0 1

Apparently only one move wins. Good luck to all the centaurs. And to all the engines without endgame tables.

[jp]

Apparently only one move wins. Good luck to all the centaurs. And to all the engines without endgame tables.

For sure. There must also be (or I hope there are) simpler examples, where "simpler" probably means some combination of fewer pieces and smaller DTM (i.e. not ~500 or ~1000). I'm hoping there are examples with DTM <100. I don't know if hoping for 50 or 75 is hoping for too much.