Trading pieces to mess up pawn structure - early game

Hi,

So I was wondering, if very early in the game I have the opportunity to trade my bishop for a knight and create a double pawn, should I do it?

As far as I know double pawns are a weakness but on the other hand, I'd be playing the same piece twice and trading a bishop for a knight which is more valuable in open games.

Thanks!

Beginners that learn about doubled pawns almost always do way too much to double the opponent's pawns.  Its like they learned too early, before they were able to put it in perspective, and they would have been better off not knowing.  

Just to not ignore the question, even if its too early, in the diagram you posted, white will not usually take that knight unless black plays a6, and even then white more often retreats it.  There are trade-offs, as you are recognizing.  Indeed, you seem to be thinking about it the right way, and I expect you'll improve quite fast, but I wouldn't worry about doubled pawns until you get a rating over 1000.  Before that, its mostly about developing fast, castling to safety and not blundering.  

so If black plays a6, why not take the knight?

The trade off at that point is not worth it? Bishop more valuable than a knight AND a double pawn on the queen side.

By trading it, I also create an isolated pawn in the A and then I can capture the central black pawn with my knight.

There is no isolated pawn created after dxc6 which is the vastly more common and preferred recapture.  An isolated rook pawn on a7 isn't necessarily a big deal in any event, because its hard to attack the pawn all the way back there.  Additionally, the pawn is not free after the capture.  It looks free, but its not; black plays qd4 (qe7 works too and would be played if bxc6) afterwards and will recover the pawn.  So, both capturing and retreating are fine and played.  Take a look here.  https://www.365chess.com/opening.php?m=7&n=275&ms=e4.e5.Nf3.Nc6.Bb5.a6&ns=3.5.5.6.5.275

Okay quite interesting!

Thank you

That's the basic trade-off involved, yes.

There is also an opportunity cost involved. If you are pursuing this goal in the opening, the other worthwhile goals (controlling the center, developing pieces, seeing to the safety of your King) must be placed on hold temporarily.

Personally, I don't think it's worth it. The cost is greater than the potential gains. It's also true that doubled Pawns are not entirely disadvantageous. The perceived weakness of doubled Pawns is often over-rated.

And I've seen a few positions where tripled pawns were not a weakness that could be exploited, making the position favor the side with the tripled pawns.

Doubled pawns might give you a pawn majority on one side of the board, perhaps a passed pawn csn be created.

The doubled pawns might be able to be undoubled later, not necessarily permanent .

The doubled pawns (if ever isolated) might be stopped by a single pawn later, making them easier to target by pieces.

Thanks a lot!

Thank you to everyone else for your answers. I thought this was a question worth asking

doubled pawns are only weaknesses if they can be attacked. If one side eats a bunch of doubled pawns but the other side checkmates the first guy, then the doubled pawns were irrelevant.

Almost true.

Another drawback of doubled Pawns is that they tend to reduce your "collective mobility". A constellation of Pawns tends to be more mobile if the Pawns themselves are organically healthy.

But this is only important in situations where Pawn mobility is important.

I like to think of a bishop as being worth 3.5 pawns and a knight as being worth 3 pawns.

2 double connected pawns are maybe worth 1.8 pawns and 2 double isolated pawns are maybe worth 1.5 pawns.

When you trade a bishop for a knight, just to give your opponent double connected pawns, you're losing 0.5 pawns worth of material, just for a 0.2 pawn positional gain. So not worth it.

If you can give them double isolated pawns though, then it's more worth it imo. And especially, if you can expose your opponent's king (eg. Bishop takes knight on f3, forcing white to play gxf3 and exposing the castled king), then it's also worth it.

The other thing to consider is space: the side with the space advantage (usually white) prefers to keep pieces on board, whereas the side that's cramped for space (usually black) prefers to trade pieces.

So that's yet another reason why you want to avoid making this trade.

Robert James Fischer would like to know your location

It's not so simple... Knight in some positions can be worth more than rook. Light square bishop at endgame with opponent's pawns  at dark squares doing probably nothing (worth, idk, maybe 1 ?), but knight is really better in this position.

When reading the answers, I think one thing is clear - there is no great advantage, or disadvantage. I would say the answer, albeit trite, is, "it depends". And it really does. Again, as the answers already given indicate, the position and what you hope to achieve, and trade to receive it, are more important considerations. Always play the position, not generalities or principles.

Also, trading a Knight for a Bishop, or a Bishop for a Knight, is a separate consideration that generally elicits interesting discussions. I believe Knights are more powerful early on when there are still many pieces on the board; while Bishops achieve maximum power as the board thins out and more open diagonals open up. But I like playing with my Knights so I'm more willing to trade a Bishop for a Knight than some others are. (I just love getting smothered mates and it's something I always look for.)

Remember, play the position, not generalities or principles, and keep in mind what you are attempting to achieve.

Personal style certainly plays a role. I prefer Bishops. When two Bishops start working together on neighboring diagonals, the results can be simply brutal, as in my "Kids, don't try this at home!" game.

https://www.chess.com/forum/view/game-showcase/a-heroic-defense-in-the-sicilian-najdorf-kids-dont-try-this-at-home-39199738

Thank you all for all these answers!

I wasn't looking for a generality but more of a reason why.. 

I like playing the exchange Ruy Lopez.  Not only does it double pawns as discussed, but most players are expecting you to just robotically play Ba4 after a6.  Perhaps it's a theoretically inferior approach.  But sometimes taking the opponent out of their comfort zone is just as important as the theory.

I agree

It is surprisingly useful to have double pawns on a board, however, when possible get it on the king's side, so it breaks the protection to the king rather than high ranking pieces. Happy Chess!