Doubled Pawns
The Doubled Queen Bishop Pawn in the Queen Pawn Opening

Point Count Chess, NO.63, p94
Example Sequence

An exchange on c3, by Black's dark-Bishop, for White's Queen Knight, results in White's Doubled Pawns on the c-file.

It also leaves White's a-Pawn Isolated, and creates a Hole at b3.

However, H&M-S suggest White benefits more from having the Doubled Pawns reinforce the Center, although there appears to be equal opportunity to win or lose, from this position (for both sides).

Beneath the ChessFlash viewer, you'll find my analysis of the position featured in Point Count Chess:
1. PCC, p94, NO.63, after 6.bxc3
2. Result of the Doubled Queen Bishop Pawn
in the Queen Pawn Opening.
3. Summary of the Doubled Queen Bishop Pawn
in the Queen Pawn Opening.
4. PGN

The Doubled Queen Bishop Pawn
in the Queen Pawn Opening
My Analysis

Position #1, My Analysis
PCC, p94, NO.63, after 6.bxc3

After: 1.d4 Nf6 2.Nf3 e6 3.c4 Bb4+B 4.Nc3 O-O 5.a3 Bxc3+ 6.bxc3

After: 6.bxc3

1. How White gains Doubled Pawns, on the c-file.

 Doubled Pawns,The Doubled Queen Bishop Pawn in the Queen Pawn Opening, After 1.d4 to 3...Bb4+ After 1.d4 to 3...Bb4+, following the advance of White's d- & c-Pawns (1.d2-d4 » 3.c2-c4) Black's dark-Bishop attacks White's King, during its developing move (3...Bf8-b4+).
 Doubled Pawns,The Doubled Queen Bishop Pawn in the Queen Pawn Opening, After 4.Nc3 After 4.Nc3, White's Queen Knight blocks the Check (4.Nb1-c3), but becomes Pinned by Black's Bb4, in the process.
 Doubled Pawns,The Doubled Queen Bishop Pawn in the Queen Pawn Opening, After 4...O-O After 4...O-O, Black delays capturing White's Pinned Nc3, to Castle Kingside (4...O-O).
 Doubled Pawns,The Doubled Queen Bishop Pawn in the Queen Pawn Opening, After 5.a3 Bxc3+ After 5.a3 Bxc3+, the attack by White's a-Pawn (5.a2-a3), prompts Black's Bb4 to capture White's Nc3, renewing the attack on White's King (5...Bb4xc3+).
 Doubled Pawns,The Doubled Queen Bishop Pawn in the Queen Pawn Opening, After 6.bxc3 After 6.bxc3, White gets Doubled Pawns on the c-file, as his b-Pawn completes the Minor Piece exchange, on c3 (6.b2xc3). Note: this position bears a similarity with No.62A, in that White also suffers an Isolated Rook Pawn (the a3-Pawn, in this case), at the same time as gaining the Doubled Pawns.

The Result of the Doubled Queen Bishop Pawn
in the Queen Pawn Opening...

 (RESULT) Doubled Pawns,The Doubled Queen Bishop Pawn in the Queen Pawn Opening, After 6.bxc3 After 6.bxc3, H&M-S question whether White's position is a fatal weakness, but cannot give a categorical answer, citing the case of Aron Nimzovich [sic], who they say: "...won games with both colors from this position..." However, H&M-S also go on to say the strengthening of the Center, from the Doubled c-Pawns, "often outweighs the Hole (b3) and the Isolated Pawn."

Summary of the Doubled Queen Bishop Pawn
in the Queen Pawn Opening...

1. Black develops his dark-Bishop, to b4. After White develops both d- & c-Pawns (1.d2-d4 » 3.c2-c4); Black's dark-Bishop comes out to Check White's exposed King, on the a5-e1 diagonal (3...Bf8-b4+).

2. Black delays capturing White's Pinned Nc3, which blocks the Check on its King. After White blocks Check with his Queen Knight (4.Nb1-c3), Black delays capturing White's Nc3, preferring to take the opportunity to Castle Kingside (4...O-O).

3. White gains Doubled Pawns on the c-file, after White's a-Pawn (5.a2-a3) prompts Black's dark-Bishop to capture White's Nc3 (5...Bb4xc3+), forcing White's b2-Pawn to complete the trade (6.b2xc3), which also leaves White's a3-Pawn Isolated, and a Hole at b3.

4. H&M-S suggest the Doubled c-Pawns helps to strengthen the Center, for White's benefit, and the c3-Hole and Isolated a3-Pawn are a price worth paying, noting that Aron Nimzovich has won games with both armies, from the position after 6.b2xc3.

PGN

[Event "PCC, p94 Diagram NO. 63"]
[Site "?"]
[Date "????.??.??"]
[Round "?"]
[White "Horowitz"]
[Black "Mott-Smith"]
[Result "*"]
[PlyCount "11"]

1. d4 Nf6 2. Nf3 e6 3. c4 Bb4+ 4. Nc3 O-O 5. a3 Bxc3+ 6. bxc3 {PCC, p94 Diagram NO.63} *

End.