Annotated Game #364: Always capture en passant

In this next tournament game, my positional troubles can be directly traced to passing up the chance for an en passant capture. While no chess decisionmaking rule is 100%, usually the burden of proof should be on not capturing en passant, whenever there is a chance for it. Here I over-estimated the worth of my advanced e-pawn and instead gave my opponent a nearly strategically won game, after what had been a rather unambitious approach by White in a Dutch Stonewall. Despite that, I perservered and achieved an equal position after sorting out my cramped pieces. My opponent, apparently disappointed in seeing her edge vanish, then decided on a somewhat speculative - but difficult to meet in practice - deflection sacrifice. At first I calculated the response well, but got tired/lazy at the end of the sequence and my opponent pounced on the mistake.

[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "Class B"] [Black "ChessAdmin"] [Result "1-0"] [Annotator "ChessAdmin/Dragon 3.2"] [ECO "A84"] [PlyCount "45"] [GameId "2345579122020421"] 1. d4 f5 2. Nf3 Nf6 3. e3 e6 4. c4 d5 {the Dutch Stonewall.} 5. Be2 c6 6. O-O Bd6 7. b3 Qe7 {the standard response to prevent White from exchanging the dark-square bishop after Ba3.} 8. Bb2 O-O 9. Nbd2 Ne4 (9... b6 $5 {allows Black to develop the light-square bishop, which has even fewer prospects than normal on the kingside, thanks to White's Be2.} 10. Ne5 Bb7 {and Black is very solid.}) 10. Nxe4 {an unambitious choice by White.} fxe4 11. Ne5 Nd7 $11 {Black should have a relatively easy game now, which however I took too much for granted.} 12. f4 Bxe5 $2 {I thought for a while here about what I considered the three main possible choices in response, and picked the worst by far.} (12... exf3 $1 {the engine shows as equal. I did not want to give up what I considered as my strong e4 pawn on (mistaken) principle.} 13. Nxf3 e5 $11 {and Black has an equally dynamic game as White in the center.}) (12... Nxe5 $6 13. dxe5 Bc5 14. Bd4 Ba3 $14) 13. fxe5 {now White's pawns are at least as strong as Black's, while the light-square bishop is better by far and the dark-square bishop can later be activated on the a3-f8 diagonal.} Rxf1+ {I recognized that my pieces were rather clogged up, so I thought exchanging would help.} 14. Qxf1 Nf8 15. Qf2 $16 {a "good enough" move by my opponent, to continue to increase the pressure on the f-file.} (15. a4 $1 $18 {with the idea of Ba3 would be strategically winning.}) 15... Bd7 $6 (15... b6 {I did consider as an alternative way of getting the bishop out. However the b-pawn's greatest utility would be in fighting for the c5 square, which becomes important later.}) 16. Rf1 $6 (16. a4 $1 {is still the way.}) 16... Ng6 $11 {now I should be fine, with my pieces untangled.} 17. Ba3 $6 {I saw this sacrificial idea (deflection tactic from f7) only after playing the previous move. It looked difficult to meet, and my opponent after much thought chose to play it.} Qxa3 {after much calculation, I decided (correctly) that this was best. All other moves in fact lose.} 18. Qf7+ Kh8 19. Qxd7 Qxa2 $15 {again the correct choice. I do not like grabbing pawns on principle, but the queen needs to stay active and make threats against the Be2 and the weak e3 pawn, and it is best to take a pawn as well. The engine evaluates this as a slight Black advantage.} 20. Qxb7 {now however I fail to grasp the needs of the position and lose. I was concerned about White's queen vacuuming up my pawns, but my own queen's activity in White's backfield would tactically defend.} Rf8 $4 (20... Rd8 $5 21. Bg4 Qd2) (20... Rg8 {was simplest to defend and the idea had occurred to me earlier, but for whatever reason I did not sufficiently consider it here.} 21. Bg4 Qd2 {White cannot defend e3 and as a result cannot bring additional forces to bear in the attack.} 22. Bxe6 Qxe3+ 23. Kh1 $11) 21. Rxf8+ Nxf8 22. Qf7 $1 {other queen moves work, but this is most forcing. I simply had not made the effort to calculate this far ahead, assuming that the lone queen could not be dangerous after the rook exchange.} Qa3 {a desperation defense, although I expected my opponent to play} 23. c5 {to block the diagonal and she did so, therefore I resigned.} 1-0