I will bet on b6-b5.

with the black queen eyeing up b5 castling now would be better.

It allows Ng4 and then Nxe3, leaving the black diagonal to the e7 bishop. Maybe I am wrong, but as white I would have tried Bf4 / Nf5 in order to pin black's pieces defending d6.

A pawn advance on the Q-side would have been worth a look: 13...b5 or maybe even 13...c4. The latter does leave the d4-square available to a White knight, so might have to be timed better. On the other hand the c5 square would enable the off-side knight back into the play. If the immediate pawn advance doesn't appeal, then the useful and thematic 13...Rfe8 is more than a temporizing move.

Why not 13...b5? I think it is the best here.

The game has developed into a Benoni/Old Indian defence hybrid. The strategic battle (very broadly speaking) will be between White's central pawn majority and K-side pressure, versus Black's Q-side majority. Black is probably hampered a bit by the location of his bishop, which would like to stand on the long dark diagonal. Maybe 14...Ng4 followed by ...Bf6 was worth considering here? (now, or even earlier)?

I agree. This is too defensive a spot.

Black's play lacks of coherence. This move secures (prematurely) the defence of d6, "freeing" the Queen, but it is not needed. On the other side, the rook was placed in d and not in e in order to allow the c7 knight to go to e1. But this is a weak plan if black doesn't exchange his f6 knight before.

This move just doesn't look very good. I agree that 15...Ng4 is better. However how else is the Nc7 going to develop?

Exactly, it was horribly miss placed to begin with.

Black's game is very difficult. I'm inclined to think the knight ought to have been left on a6 until Black had some positive plan for its relocation (mind you, maybe he does). 15...Ng4 is attractive here, hoping to exchange on e3, but after 16.Bd2 it's not so easy to find a good continuation. I might try 15...b5 in this position... or 15...Re8.

Why not Nc7-b5? Eventually, it will go to d5, giving white a pawn after the exchange, but it opens the c coumn to black, giving some space and counterattack.

There was something to be said for leaving the option open for Black, with the view to 16...Ng4 17.Bd2 Ne5 (say) 18.f4, or variations upon that theme.

The natural move for the f pawn is f4. If white wants to block Ng4, h3 would have been better in my opinion. White gets a good game because of black's lack of attack on the queen side.

It was good to double up on the c-file. White sees that it will soon be opened up.

Shrink-wrapped development...

That is not en-prise. That is just undefended. Had the knight already been on f5, it would have been en-prise - 'to be taken'

black now plays ...Nf8-g6-e5 which is pointless and shows that black has no real plan. just 18...Ne5 is much simpler and better.

18...Bf6 with a view to fiachettoing "longhand" by 19...g6 and 20...Bg7 and Black's game doesn't look too bad. 18...Ne5 19.f4 Ng4 20.Bd2 with 21.h3 to come looks pretty good for White. Black has played rather pessimistically so far (probably underestimating his resources), but White has been taking his time also.

Very good way to resume the game so far, in my opinion.

"Attack in the direstion the pawns are pointing". This does indicate a Q-side attack, but White could attack just about anywhere he likes, now.

The Ng6 is not a very effective piece. It's best hope is to swap off on e5.

On g6 the knight does help to restrain White's e-pawn. An e4-e5 break by White is one of the motifs of this kind of position - something always has to beware of. Is it the best move? I still like ...b5 or ...Bf6

Tactical error. The game is as good as over now.

A comment symptomatic of Black's pessimistic play - bordering on defeatism (sorry sf115!). White has the better of it, sure, but he still has to "prove" it. Cramped though it is, Black's position is not yet bereft of resource or resilience.

Agreed, I found sf115 to be overly defensive and missed a great number of opportunities. Don't worry though as your game improves so too will your confidence.

Also worth a look was 22.Bd4, planning to exchange on e5. If 22...Ng6 then [a] 23.Nxe7+ Qxe7 24.Nc6 Rxc6 25.Bxf6 Qxf6 26.dxc6 or [b] 23.Nxe7+ Nxe7 24.Bxf6 gxf6 25.f4

After Nxe7, Qxe7, black cannot take the knight in b4 because he loses on c8 exchanges... )) ah, wonderful...