The Owen's defence is a chess opening which starts with 1. e4 b6!?. This opening is playable if Black can get a quick c7-c5 break, where he has a pawn on e6, b6, and then he pushes c7-c5.

However, Stockfish on 22ply depth disagrees, giving White a +0.89 advantage. This hardly seems playable, as White has almost the advantage of an extra pawn.

So there must be a reason for this evaluation. I think that White can somehow prevent the break, to get a full pawn center, but I can't find any way to do so without compromising my pawn structure.

  • 3
    Forget about engines for opening evaluation. Even if black manages to get that ...c5 push, the best thing that can happen is that they'll get a worsened version of other openings (like the Sicilian or French defences)
    – David
    Commented Sep 17, 2020 at 8:56

3 Answers 3


Stockfish's @.3484814232843 shouldn't concern Black as much as Morphy's simple plan for White.

1.e4 b6 2. d4 Bb7 3. Bd3 e6 4. Nh3

Stockfish might be complaining because White gets free rein in the center, but Morphy said 'two pawns is enough', then as long as White continues developing, he's guaranteed at least equal development, and because it was the fastest possible kingside development, White has O-O plus f2-f4-f5 in store to open a file.

1...b6 made it too easy for Morphy (and anyone) to follow the general winning plan of better center control, better development, better king safety, then from that superior position, attack the enemy king by opening files for the rook.

See Morphy-Lewis, Philadelphia 1859. Trust Morphy's practical chess wisdom over Stockfish's analysis. stockfish might tell you how much it's bad, but Morphy showed us how and why.


It's completely playable below master level, probably playable to IM level and probably useful occasionally as a surprise weapon at GM level. Combined with the English defense it gives black a very solid opening repertoire with very little theory to learn. The only caveat would be to just be careful castling kingside into a strong attack.

22 ply is 11 moves. How many players below master level analyze 11 moves deep in their opening prep let alone over the board? If you can see two moves ahead you're better than most of the players out there and probably wouldn't be asking this question.

A .89 evaluation is literally nothing below GM level. Analyze your games with an engine. How many times do you see a swing bigger than .89 on a single move? I'm guessing at least once a game. And even if you do play near perfect chess how big a difference is there between that and the alternatives? I'm looking at the 365chess.com database. It has 1...b6 at .66 at a depth of 38. It has other mainstream openings like the French (.53), Pirc (.6) modern (.62), Alekhine's (.55) etc. You're literally talking about tenths and even hundredths of a pawn. It's absurd for players below master level to be talking about differences that small.

  • 1
    Even at my level, well below master one, and in the internet blitz, my winrate against openings like 1...b6 is much higher than against normal ones. The reason is that they are 0.66 only if black knows what they are doing, and they are much harder to play with black than with white, whose play is straightforward.
    – Kostya_I
    Commented Sep 17, 2020 at 21:05

You put too much faith in engines and too little respect for how actual people really play.

b6 is more than playable. I would not venture it against a GM but for any tournament I could seriously compete in it would work --IF it were compatible with my style which it is not. When they play b6 I generally win. That has more to say about me and my experience, or their weaknesses ,than the opening move.

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