[im3w1l]

Human players have this concept of progress. I couldn't give a good succinct description of exactly what that entails, but basically if you are trading off pieces that's progress, if your king is breaking through the defensive formation of the pawn endgame that's progress. If you are pushing your passed pawn up the board that's progress. If you are slowly constricting the other king that's progress.

When we have a won position we want to progress and convert it to an actual win.

I think the operational definition I would use for progress is a prediction of how many more moves the game will last. A neural network can be used for that.