Morphy Invariably Played the French 3.exd5

While working on my latest 'Every Move Explained, 1969 Sarajevo - Kovacs vs Korchnoi, I discovered a mention by Tarrasch that Morphy 'invariably adopted' the Exchange Variation of the French Defense, 3.exd5.

Since I'm always intrigued by logical inconsistencies, I decided to investigate. I found 10 Morphy games that started 1.e4 e6, followed by 2.d4, the only move played by Morphy. Six games continued 2...d5 (Anderssen played 2...g6?!), when Morphy played 3.exd5. Here's a PGN-compatible opening tree showing game counts for each move.

1.e4 e6 2.d4 {x10} 2...d5 {x6} (2...g6 {x2}) (2...c5 {x1}) (2...c6 {x1}) 3.exd5 {x6} 3...exd5 {x6} 4.Nf3 {x6} 4...Nf6 {x3} (4...Bd6 {x2}) (4...Be6 {x1}) 5.Bd3 {x3} 5...Bd6 {x4} (5...Be6 {x2}) 6.O-O {x4} 6...O-O {x4} 7. Nc3 {x4} 7...c6 {x2} (7...c5 {x1}) (7...Bg4 {x1}) 8.Bg5 {x2} 8...h6 {x1} ( 8...Bg4 {x1}) 9.Bh4 {x1} 9...Bg4 10.h3 Bxf3 11.Qxf3 Nbd7 *

The main line is from Morphy's 1958 match against Loewenthal.

[Event "London m"]
[Site "London"]
[Date "1858.07.19"]
[Round "10"]
[White "Morphy,Paul"]
[Black "Loewenthal, Johann Jacob"]
[Result "1-0"]
[Eco "C01"]

1.e4 e6 2.d4 d5 3.exd5 exd5 4.Nf3 Nf6 5.Bd3 Bd6 6.0-0 0-0 7.Nc3 c6 8.Bg5 h6 9.Bh4 Bg4 10.h3 Bxf3 11.Qxf3 Nbd7 12.Bf5 Qc7 13.Rae1 Rae8 14.Re3 Bf4 15.Re2 Rxe2 16.Nxe2 Bd6 17.Bxd7 Nxd7 18.Ng3 Re8 19.Nf5 Nf8 20.Bg3 Bxg3 21.fxg3 Re4 22.c3 Nh7 23.h4 h5 24.c4 Nf6 25.Nxg7 Ng4 26.Nxh5 Rxd4 27.Nf6+ Nxf6 28.Qxf6 Rxc4 29.Rf5 Rg4 30.Re5 Qc8 31.Re7 Qf8 32.Qe5 Qg7 33.Re8+ Kh7 34.Qh5+ 1-0