Value of an isolated passed pawn in endgame ?

[Henk]

Just played a blitz game with Queen + three extra isolated passed pawns on row four and three against Rook, Knight and Bishop. Both having some other pawns.

But Skipper playing with the queen was loosing this endgame quickly though evaluation value said +2

[Sven]

Just played a blitz game with Queen + three extra isolated passed pawns on row four and three against Rook, Knight and Bishop. Both having some other pawns.

But Skipper playing with the queen was loosing this endgame quickly though evaluation value said +2

Maybe like in this example?
[d]
SF search shows 0.00 quickly. Output of "eval" command (all numbers in cp):

Code: Select all

      Eval term |    White    |    Black    |    Total
                |   MG    EG  |   MG    EG  |   MG    EG
----------------+-------------+-------------+-------------
       Material |   ---   --- |   ---   --- |  0.67  1.17
      Imbalance |   ---   --- |   ---   --- | -0.12 -0.12
          Pawns |   ---   --- |   ---   --- | -0.45 -0.46
        Knights |  0.00  0.00 |  0.22  0.04 | -0.22 -0.04
         Bishop |  0.00  0.00 | -0.06 -0.09 |  0.06  0.09
          Rooks |  0.00  0.00 |  0.17  0.08 | -0.17 -0.08
         Queens |  0.00  0.00 |  0.00  0.00 |  0.00  0.00
       Mobility |  0.21  0.36 |  0.47  0.91 | -0.26 -0.55
    King safety |  0.51 -0.06 |  0.51 -0.06 |  0.00  0.00
        Threats |  0.00  0.00 |  0.00  0.13 |  0.00 -0.13
   Passed pawns |  0.23  0.52 |  0.00  0.00 |  0.23  0.52
          Space |  0.03  0.00 |  0.02  0.00 |  0.01  0.00
----------------+-------------+-------------+-------------
          Total |   ---   --- |   ---   --- | -0.27  0.25

Total Evaluation: 0.26 (white side)

So the value of the passers is not very high for Stockfish (+0.50 cp in total roughly), and the isolated pawns are scored as roughly -0.15 cp each. Material is about +1 for White but Black has three pieces and therefore some mobility bonus is added for Black.

Having lost the game is most probably a result of more than just an over-optimistic evaluation, though.

[Henk]

King safety of white was much worse so perhaps Kc2 and white pawn on g4 instead of g2

[Eelco de Groot]

Added to that, three isolated pawns is three targets, and with three attacking pieces no wonder that the queen can get in trouble trying to defend them all. As long as the side with three pieces can also still create a passer that side can win in theory. But any passed pawn moving up from row four will gain value quickly, so without more specifics on the position, trying to give advice on adjusting the value of isolated pawns is I think just guesswork. +2 for the static eval could still be true, if that +2 is for the passed pawns alone that is a bit much I think.

[Eelco de Groot]

King safety of white was much worse so perhaps Kc2 and white pawn on g4 instead of g2

It is an endgame so the term King Safety is a bit awkward, but if you mean king could not protect the pawns on the Kingside (g4, h3), then yes that is a handicap. I dont think Stockfish even has a static evaluation term for that, it is like the weak pawn a3 in the opposite coloured bishop endgame that Lyudmil mentioned and opponent king better placed than defending king with respect to he pawns at the base of a chain.

[Henk]

After fifteen moves or so White's king was check mated by those three pieces on first row.

[Sven]

After fifteen moves or so White's king was check mated by those three pieces on first row.

Who was playing for Black?

[Henk]

After fifteen moves or so White's king was check mated by those three pieces on first row.

Who was playing for Black?

Fairy max. Might also be twenty or twenty five moves. In these blitz games moves go so fast you are easily mistaken about number of moves.


I remember Skipper was not able to get a pawn behind row 5.

[Sven]

After fifteen moves or so White's king was check mated by those three pieces on first row.

Who was playing for Black?

Fairy max. Might also be twenty or twenty five moves. In these blitz games moves go so fast you are easily mistaken about number of moves.


I remember Skipper was not able to get a pawn behind row 5.

And you are playing engine-engine games without saving the game as PGN? Then how would you ever be able to analyze what happened and why, and how could anyone help you in this case, if you don't have the concrete position and game?

[Daniel Anulliero]

After fifteen moves or so White's king was check mated by those three pieces on first row.

Who was playing for Black?

Fairy max. Might also be twenty or twenty five moves. In these blitz games moves go so fast you are easily mistaken about number of moves.


I remember Skipper was not able to get a pawn behind row 5.

And you are playing engine-engine games without saving the game as PGN? Then how would you ever be able to analyze what happened and why, and how could anyone help you in this case, if you don't have the concrete position and game?

Yes Sven , chess programming is all about very good méthodology and also so good PC with not windows 10 of course