Calculating space

[PK]

Stockfish depends space as "squares on 3rd to 5th rank, behind pawns, edge files excluded, not attacked by enemy pawns and attacked by our pieces". Toga II 3.0 gives a non-linear bonus for pieces on enemy half of the board (the more the better). Neither approach worked for me, but it probably varies from engine to engine. Anyhow, space eval seems just a correction to whatever piece/square tables and mobility do wrong.

[D Sceviour]

Toga II 3.0 gives a non-linear bonus for pieces on enemy half of the board (the more the better).

I have using an approach similar to the Toga approach mentioned for some time. If I take it out, then the program plays weaker. This is an indication that "space" value is primary and crucial to the total evaluation. That is, space is one of the four corner stones of chess being: material, space, time and pawn structure. You cannot simply adjust a space value. I think space has to be considered first and then other values adjusted around it. Of course, this is only my conclusion but it seems to be supported by a number of chess authors. Still, if I am wrong then tell me how to remove a space calculation without damaging the search.