Portuguese Opening: 1. e4, e5 2. Bb5

@ JogoReal and Elvis_4720 - What have your results been like when your opponent has played 2...c6? This seems to be the real test for this opening, as discussed above.

@ Karpark

After 1. e4 e5 2. Bb5

        Move      Frequency    Score  Draw

     1: c6        896: 41.3%   69.2%   5% -0.14

     2: Nf6       450: 20.7%   74.2%   5%   

     3: Bc5       221: 10.2%   77.6%   3% +0.08

     4: a6        214:  9.8%   67.7%   4% +0.01

     5: Nc6       200:  9.2%   70.0%   7%

     6: Qg5        53:  2.4%   60.3%   0%

     7: Qh4        46:  2.1%   63.0%   9%

     8: f5         19:  0.8%   60.5%   5%

     9: Qf6        11:  0.5%   95.4%   9%

    10: Be7        10:  0.4%   90.0%   0%

    11: Bb4         9:  0.4%   88.8%   0%

    12: Bd6         8:  0.3%   43.7%   0%

    13: Qe7         5:  0.2%   80.0%   0%

    14: Ne7         5:  0.2%  100.0%   0% +0.50

    15: a5          3:  0.1%   33.3%   0%

    16: c5          3:  0.1%  100.0%   0%

    17: h6          3:  0.1%  100.0%   0%

    18: b6          2:  0.0%  100.0%   0%

    19: f6          2:  0.0%  100.0%   0%

    20: Nh6         2:  0.0%  100.0%   0%

    21: g6          2:  0.0%  100.0%   0%

    22: h5          1:  0.0%  100.0%   0%

    23: Na6         1:  0.0%   50.0% 100%

    ___________________________________________

    TOTAL:       2166:100.0%   71.0%   5%

Note: Exported from a "Scid vs PC" tree with mask, some computer evaluations are added by me as comments.

Now after 1. e4 e5 2. Bb5 c6 3. Ba4

        Move      Frequency    Score  Draw

     1: Nf6       325: 36.2%   67.3%   5%   

     2: b5        208: 23.1%   78.6%   5% +0.24

     3: d5        204: 22.7%   62.5%   7% -0.34

     4: Bc5        49:  5.4%   65.3%   4%

     5: d6         31:  3.4%   87.0%   0%

     6: Qg5        25:  2.7%   50.0%   4%

     7: Na6        12:  1.3%   62.5%  17%

     8: Qa5         9:  1.0%   77.7%   0%

     9: a5          8:  0.8%   75.0%   0%

    10: f5          6:  0.6%   41.6%   0%

    11: Ne7         4:  0.4%  100.0%   0%

    12: a6          4:  0.4%  100.0%   0%

    13: Qh4         2:  0.2%   50.0%   0%

    14: Nh6         2:  0.2%  100.0%   0%

    15: Qf6         1:  0.1%  100.0%   0%

    16: Bd6         1:  0.1%  100.0%   0%

    17: Bb4         1:  0.1%    0.0%   0%

    18: Be7         1:  0.1%  100.0%   0%

    19: Qb6         1:  0.1%  100.0%   0%

    20: [end]       1:  0.1%  100.0%   0%

    21: b6          1:  0.1%    0.0%   0%

    22: g6          1:  0.1%  100.0%   0%

    ___________________________________________

    TOTAL:        897:100.0%   69.2%   5%

Thanks. Can I ask how you interpret these figures for 2...c6?

       Now after 1. e4 e5 2. Bb5 c6 3. Ba4 d5

        Move      Frequency    Score  Draw

     1: Nc3       199: 97.5%   62.0%   7% -0.66

     2: exd5        3:  1.4%   66.6%   0% -0.22

     3: Qe2         2:  0.9%  100.0%   0%

    ___________________________________________

    TOTAL:        204:100.0%   62.5%   7%

After 1. e4 e5 2. Bb5 c6 blacks have a slight advantage. Being a rare opening if whites know it better than blacks (as usual) this can compensate a bit.

Thanks. I trust your knowledge and experience as, unlike you, I've never played the Portuguese Opening. However I think I'll stick with 2. Nf3 as white for now! 

Im trying this just because I'm portuguese

Sure, that line is good and solid for blacks. My Stockfish evaluate it as -0.14. It is not the traditional main line. Main line is 3...Nxe4, and not so good in my view.

The value of the opening comes when you put the opponent playing with blacks an opening he don't know and an opening that, like all open games, is rich in traps and tactics. If you follow the best lines by the computer it can easily get a small advantage for the blacks. Anyway computers almost never play "The Portuguese".

The problem with moves like 2. Bb5 is that they commit pieces very early, letting the opponent easily adjust to the circumstances. What business does the bishop have on b5? Usually the Bb5 move is made to pin the c6 knight and, as such, to put more pressure on the e5 pawn. But here, the knight isn't on c6 yet... So why do it? Just to develop the bishop randomly? After eventual ...c6, the bishop will have to drop back, and black will be able to continue with ...d5, gaining a strong center.

2.Bb5 is an obvious mistake that is why it not even a named opening, it is a blunder.

It's suboptimal but non-refutable.

Come on, it's not even an inaccuracy.

Considering computer analysis evaluations, after 1. e4 e5, 2. Bb5 is not objectively worse than 2. f4, the move of the King's Gambit. Maybe the books should move its name to "King's Bishop Pawn Blunder", so...

"2.Bb5 is an obvious mistake that is why it not even a named opening, it is a blunder."

I mean sure it's playable as anything else. I don't like playing against 2...Nf6 which seems to just ignore White's ideas and work out in the end. 3.d3 and 3.Qe2 look interesting to me and aren't the main moves but I think 3.d4 just leads to a typical middlegame that isn't all that surprising to anyone.

What "typical middle game" is that after 1.e4 e5 2.Bb5 Nf6 3.d4? Can you show us a game?

This doesn't look like difficult play to me and there are similar positions in many other king's pawn openings.