"Cleanly" in chess parlance means you're up a pawn, and there is no "compensation" for the other player. I.e there are no other advantages in the opponents posi

"Cleanly" in chess parlance means you're up a pawn, and there is no "compensation" for the other player. I.e there are no other advantages in the opponents position that make up for the fact they're down a pawn(things like an attack on your king, piece activity, pawn structure). In simple mathematical terms a clean material advantage is: Overall eval >= material eval If overall eval < material eval, then compensation(other player) > 0 = "the opponent has some compensation for the pawn"