Pawn Masses

Here are useful and simple rules of thumb: Two connected passed pawns on the 5th rank are generally worth a knight or bishop; Two connected passers on the 6th rank are generally worth a rook; And two connected passers on the 7th are generally worth a queen.

But what's the value of having more than two advanced connected passers? There's nothing in chess as intimidating as a pawn storm, a cluster of connected pawns rolling down the board as part of a coordinated attack. That's what this e-bo...