Black's defense against 1. e4
I looked at eight different responses to 1. e4 listed in chess opening theory. They are c5, d5, e5, c6, d6, e6, g6, and Nf6. For each response I played out 10 mainline opening moves and then compared the relative advantage gained by black in each of the defenses.
I guaged the relative advantage using the positional value computation of the engines on a scale in which the material value of a pawn is 100. At the start white holds an edge of 18 points by virtue of owning the first move. We compare this advantage to the positional value after 10 moves to evaluate the effectiveness of black's defense. The selection of 10 as the number of moves to play is somewhat arbitrary but it probably does get us to the end of the opening. Anyway, here are the results.
(a) 1. e4 c5
1. e4 c5 2. Nf3 Nc6 3. Bb5 g6 4. Nc3 Bg7 5. O-O Nf6 6. e5 Ng4 7. Bxc6 dxc6 8. Re1 O-O 9. d3 Nh6 10. Ne4 b6
White's starting advantage = 18
White's ending advantage = 7
Black gains 18- 7 = 11 points
(b) 1. e4 d5
1. e4 d5 2. exd5 Nf6 3. d4 Qxd5 4. Nc3 Qd8 5. Nf3 e6 6. a3 Nc6 7. Bc4 h6 8. O-O Bd6 9. Qe2 O-O 10. Ne4 Re8
White's starting advantage = 18
White's ending advantage = 45
Black loses 45 - 18 = 27 points
(c) 1. e4 e5
1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Bxc6 dxc6 5. O-O Qf6 6. d4 exd4 7. Bg5 Qd6 8. Qxd4 Qxd4 9. Nxd4 Bd6 10. Ne2 Bg4
White's starting advantage = 18
White's ending advantage = 7
Black gains 18 - 7 = 11 points
(d) 1. e4 c6
1. e4 c6 2. d4 d5 3. Nc3 dxe4 4. Nxe4 Nf6 5. Nxf6+ exf6 6. Nf3 Na6 7. a3 Nc7 8. Bd3 Qe7+ 9. Be2 Be6 10. O-O Qd7
White's starting advantage = 18
White's ending advantage = 24
Black loses 24-18 = 6 points
(e) 1. e4 d6
1. e4 d6 2. d4 Nf6 3. Nc3 Nbd7 4. Nf3 e5 5. Be2 Be7 6. a4 O-O 7. O-O exd4 8. Qxd4 Re8 9. Rd1 Bf8 10. Be3 c6
White's starting advantage = 18
White's ending advantage= 31 points
Black loses 31-18 = 13 points
(f) 1. e4 e6
1. e4 e6 2. d4 d5 3. exd5 exd5 4. Nf3 Nf6 5. Bb5+ c6 6. Bd3 Bd6 7. Qe2+ Be6 8. Ng5 Qe7 9. Nxe6 Qxe6 10. Qxe6+ fxe6
White's starting advantage = 18
White's ending advantage = 10
Black gains 18 - 10 = 8 points
(g) 1. e4 g6
1. e4 g6 2. d4 Bg7 3. Nf3 d6 4. Nc3 Nf6 5. Be2 O-O 6. O-O a6 7. a3 Nc6 8. d5 Ne5 9. Nxe5 dxe5 10. Bg5 Qd6
White's starting advantage = 18
White's ending advantage = 27
Black loses 27-18 = 9 points
(h) 1. e4 Nf6
1. e4 Nf6 2. e5 Nd5 3. c4 Nb6 4. d4 d6 5. exd6 exd6 6. Nf3 Bg4 7. Be2 Be7 8. O-O O-O 9. h3 Bxf3 10. Bxf3 Nc6
White's starting advantage = 18
White's ending advantage = 37
Black loses 37-18 = 19 points
To be sure these differences in positional value are very small and can surely be overcome by tactical play but it may be useful for the black player to note the following:
1. Of the 8 responses by black 3 are winners and 5 are losers.
2. The winners are 1. e4 c5 (+11), 1. e4 e5 (+11), and 1. e4 e6 (+8)
3. The losers are 1. e4 d5 (-27), 1. e4 Nf6 (-19), 1. e4 d6 (-13), 1. e4 g6 (-9), 1. e4 c6 (-6)
These data appear to suggest that black does not gain any advantage by playing d5 (Scandinavian), Nf6 (Alekhine), d6 (Pirc) or g6 (Modern) unless he or she has a specific strategy, trick, or trap up their sleeve that is faciilitated by these openings. I would think that players rated under 2000 would want to shun the losers and stick with the tried and true defenses such as e5 ane c5. I was surpirsed to find that e6 appears to be just as good as e5 and leads to more complex positional possibiilities for advanced players.
I should add that I computed the pooled variance of all 161 positional values as 12.6 which means that the standard deviation is 3.55. These values do tend to jump around from move to move and so there are probably not statistically significant differences among these values except possibly for the extreme ends of the data. For example, 1. e4 e5 is surely a better defense than 1. e4 d5. Personally I would not want to play any of the loser defenses except to explore the possibilities.
Cha-am Jamal
Thailand
