Which pawn to capture with?

I came to the following position in a game.

Which pawn should I have captured with?

In the opening you capture towards the center.  In the end game, you capture away from the center.  The reason being that the farther apart the pawns are the harder it is for the opposing king to defend against them.

In the long term, capturing towards the center (with the a pawn) would be better, because your c pawn is a passed pawn and it has potential to claim the center with support from your upcoming b pawn.  However, this situation is tactical.  Taking with the a pawn means the c pawn is only defended by your queen, so look for tactics that would force the queen to move or add more attackers on the c pawn.  I don't see any obvious tactics, however.

4 this position capture away from the centre followed by attacking white's lone pawn with the rook(& queen guards that pawn's advancing square without getting overloaded)

but 4 a general opinion (i m not quite sure but) too many pieces means create as many passed pawns as possible if u have the majority on that side

During the game, I captured with the c-pawn partly because of the idea of keeping my pawns as far away from the enemy king as possible and I wasn't sure yet if my opponent would be able to use his a-pawn to split my joined pawns.

The reason I asked is because during the computer analysis part of my analysis, Fritz said to capture with the a-pawn.

Even when I saw this I disagreed with it, but thought I'd put it out there to see if my choice was actually the correct one.

I suppose, in Fritz's defense. It may have figured whites a-pawn was lost anyway and the c-pawn could help in adding pressure to the center.

Since it is a middlegame you should have captured with the a pawn. The a and b pawn are out of game, they cannot control the center. Also, in this position it would have allowed you to attack the a pawn.

In general postal players prefer capturing towards the center, although in timed chess it is sometimes better capturing away from the center to create more chances of an out side passed pawn and more dynamic imbalance. Of course all of these generalities are trumped by precise calculation of the position in question. Here, black has a permanently weakened position around his king and is a pawn down, so will probably lose whatever he does against best play. However, central play for best chances would indicate an intermezzo followed by shoring up d4, namely:

1...Bc4
2.Nd3 Bxd3
3.Qxd3 axb6
4.Rfd1 c5

1...Bc4
2.Nd3 Bxd3
3.Qxd3 axb6
4.Rfd1 c5

However, I'll add that white should still win this position, so this ends up as the question "what's the best move from a lost position?"

This makes absolutely no sense at all. Timed game or not, the same principles of a situation like this are going to be valid.

kleelof

Black's pieces are better developed.  After black captures with the a pawn, he can get control over the center.

I would capture with the c pawn.

You can avoid a backwards pawn and still create a passed pawn in the future. Capturing with the a pawn it seems the pawns could get weak.

They both look viable. Without calculating anything or putting it in an engine, cxb looks more intuitive, but I think this is an illusion. Either way, they are basically equally as weak because you don't have a real pawn chain, just two connected pawns. Probably axb is better.

Intuitively, the a pawn is the best capture for a few reasons.  First of all, you open the a file against white's isolated a pawn.  Secondly by keeping your c pawn you don't activate white's rook.  Thirdly you preserve your c pawn which can potentially affect center squares (e.g. anchor a piece on the d file or keep an enemy piece out).  Lastly, that the c pawn is weak or backward is an illusion... there's nothing stopping it from advancing (in fact it's a passed pawn).

When I first saw it, I thought it was an interesting position and I wasn't sure.  Especially because a rook on a8 may be denied or kicked by white's bishop.  But when I realized the c pawn wasn't weak it became obvious to me (and the a pawn is permanently weak, no need to be able to attack it immediately).

The computer happens to agree with me.  Whether or not my reasoning was correct though I'll let a stronger player decide.

And take this with a grain of salt, but IMO I think it's useful to focus / improve your ability to solve mini logic puzzles like this.  I think this is one important reason for why stronger class players and experts have much more efficient analysis when compared to lower class players.

And I don't know what player said to capture towards the center in middlegames and away in endgames... probably some GM or something, but really rules of thumb like this... I don't know, they seem silly.  Analyze the position, don't reach for a cop-out.  In many endgames the flank pawns offer your opponents drawing chances.

After reading the responses here and looking at it all again I think capturing with the a pawn would have been better. For the following reason: every move should try and accomplish multiple tasks.

Capturing with th c pawn can only be justified by saying it was done to deal with 1 single pawn.

Even during the game I could see keeping the c pawn had multiple benefits. And now I can see it had a couple of more.

Thanks everyone for your comments.