If black ignore 9.e5, then white will capture on d6, giving black double isolated pawns (c6 and c5) which is a major structural defect.
If black plays a move like 9...d5 then white wins a free pawn with 10.Bxc5
e5 was a good move at various points later in the game for the same reason.
Very helpful, thanks.
Just to add (and implied by @llama47) after your opponent played Nf6, the capture on e5 is forced because you can fork the knight and d pawn. Then your opponents pawns on c6 and e5 are both hanging and attacked by your bishop and knight respectively. f7 and c6 are weak. Nxe5 attacks the queen and puts pressure on both those pawns. Your opponent's king was still in the centre and there was an opportunity to take the initiative by creating some problems for them to solve. Maybe they could play Qd6 to hold the centre, but she is dangerously exposed and you have Na4 to maintain pressure on c6, and then if they castle Bxc5 wins a pawn and skewers the rook. I think you had some good positional and tactical opportunities. I dont see that trading off your bishop did anything for you and only helped solve some problems for your opponent. Just some things to think about.
Sorry my predictive text converted c5 into c6 but hopefully you get the idea.
Have a think about why you traded off the dark squared bishop. Was it an impulsive, just something to attack? As I see it, your opponent wants to play d5 at some point, but while your bishop maintains pressure on c5, they cant push the d pawn. c5 needs more support. Trading off the bishop solves a problem for them by easing central pressure. Try to understand what your pieces and pawns are doing. Good luck.
Hi there,
In this game: