Why does Stockfish take here (I didn't)

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Avatar of Machariel

In a practice match I played with white...

... up until move 4. Stockfish took on move 5 with cxd. I played 5. e3 instead and didn't think taking black's d-pawn is such an urgency - so to speak. What could be the motivation to take the d-pawn already?

Avatar of notmtwain
Machariel wrote:

In a practice match I played with white...

... up until move 4. Stockfish took on move 5 with cxd. I played 5. e3 instead and didn't think taking black's d-pawn is such an urgency - so to speak. What could be the motivation to take the d-pawn already?

I think the point of taking it is to eventally play Qb3, forking the b7 and d5 pawns after taking care of the d4 pawn and developing a bit.

Avatar of Machariel
notmtwain wrote:
 

I think the point of taking it is to eventally play Qb3, forking the b7 and d5 pawns after taking care of the d4 pawn and developing a bit.

I guess, but it's easy to prevent that from happening.

Avatar of inkspirit
White is going to play cxd5 sooner or later, as he needs the c-file for his rooks. Black, on the other hand, wants to trade pieces and ease the pressure on his position, which means that he prefers to recapture on d5 with his f6-knight if possible.

As an example, 5. e3 Nf6 6. a3 Be7 7. cxd5 Nxd5 and a pair of light pieces will be off board.

A similar idea occurs in 5. e3 Nf6 6. a3 Be7 7. Nf3 O-O 8. Be2 dxc4 9. Bxc4 Na5 10. Be2 Nd5. See that ...Nd5 is an important step in black’s path to equality? Therefore 4. cxd5, preventing ...Nd5, is preferred.

Avatar of drmrboss

After quick analysis with Leela and stockfish on my phone, they both prefer cxd5.

 

both cxd5 and e3 are strong logical moves, both are acceptable. No point wasting time which line is better. All chess games leads to either of three outcome game  and the choice of both cxd5 or e3 would lead to draw as the position is still equal.( neither of them would change outcome from draw / lose/ win )

For reference of Lco and SF lines.



Avatar of Machariel
drmrboss wrote:

both cxd5 and e3 are strong logical moves, both are acceptable. No point wasting time which line is better. All chess games leads to either of three outcome game  and the choice of both cxd5 or e3 would lead to draw as the position is still equal.( neither of them would change outcome from draw / lose/ win )

Yes I agree. @inkspirit added something crucial: starting off from your engine analysis, the key difference is that with e3 first, black can play Nf6 and on some next move take with the Knight on d5! A nifty little detail.

Thanks to everybody for your contribution again!

Avatar of old_acc_mm
drmrboss wrote:

After quick analysis with Leela and stockfish on my phone, they both prefer cxd5.

 

both cxd5 and e3 are strong logical moves, both are acceptable. No point wasting time which line is better. All chess games leads to either of three outcome game  and the choice of both cxd5 or e3 would lead to draw as the position is still equal.( neither of them would change outcome from draw / lose/ win )

For reference of Lco and SF lines.



Which mobile app is that?

Avatar of drmrboss
MangoMankey wrote:
drmrboss wrote:

After quick analysis with Leela and stockfish on my phone, they both prefer cxd5.

 

both cxd5 and e3 are strong logical moves, both are acceptable. No point wasting time which line is better. All chess games leads to either of three outcome game  and the choice of both cxd5 or e3 would lead to draw as the position is still equal.( neither of them would change outcome from draw / lose/ win )

For reference of Lco and SF lines.



Which mobile app is that?

Do you mean Leela?

https://github.com/LeelaChessZero/lc0/wiki/Running-lc0-on-Android-with-a-chess-GUI

 

Android leela is  much weaker (200-300 elo) than droidfish. I just do double check for Stockfish as Stockfish do mistakes in certain openings ( e.g French, Catalan). If you have Nvidia GPU, leela is much stronger than SF in opening preparation.