The Power Of Two Knights

KEVIN O'Rourke posted on the English Chess Forum yesterday afternoon:

We’ve all heard and experienced the Bishop pair from hell but are there any good and reoccuring reasons to try and keep both knights and use them as a weapon till well into the game?
They say Knights are better in cramped positions but that’s not always the case if the board is too cramped.

A search of a database of my games brings up the following example from my early days of tournament chess.
Spanton (147) - Justin Baptie (164)
British Major (Eastbourne) 1990
Spanish Exchange
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Bxc6
White acquires the knight-pair, and damages Black's pawn-structure into the bargain.
4...dxc6 5.d4 exd4 6.Qxd4 Qxd4 7.Nxd4 Nf6 8.f3 g6!?
There is only one example of this move in ChessBase's 2020 Mega database - played by a 2076 in 2017.
9.c3 c5 10.Ne2 Bg7 11.Bf4 c6 12.Be3 c4 13.Nd2 b5
Black has gained queenside space, but he cannot easily create a passed pawn there and his pawns can become fixed and inflexible.
14.0-0-0 Nd7 15.Bd4 Ne5 16.Bxe5 Bxe5
Now we have an example of a pure knight-pair versus bishop-pair with no other minor pieces on the board.
17.f4 Bc7 18.Nf3 Bb7 19.Rd2 Ke7 20.Rhd1 Rad8 21.Rxd8 Rxd8 22.Rxd8 Bxd8
And now all the heavy pieces have disappeared, so it is the purest possible example of knight-pair versus bishop-pair.

Knights versus bishops

23.Kd2 h6 24.Ke3 Bc7 25.e5 Bc8 26.Nd2 Be6 27.g3 f6 28.exf6+ Kxf6 29.Ne4+ Ke7 30.Nd2 Bb6+ 31.Nd4 Bd5 32.Ne4 a5 33.a3 Be6 34.Nf2 Bd5 35.g4
35.Ng4 looks strong at first glance as 35...h5? loses a pawn to 36.Ne5, since 36...Kf6?? loses the game to 37.Nd7+. But Black can play 35...Kf8, when 36.Nxh6 Be6 seems to be only a draw, eg Komodo10 and Stockfish10 give 37.g4 (37.Ke4 Bd5+ 38.Ke5? Kg7) Kg7 38.g5 Ba7 39.Kd2 (39.Ke4 Bd5+ 40.Ke5?? Bb8#) Bxd4 40.cxd4 b4 with equality.
35...Bg2 36.h4 c5?
It seems difficult for White to make progress after the patient 36...Bd5.
37.Nf3?!
I cannot recall why I did not play 37.Nxb5, as 37...Bc6 is met by 38.a4, but perhaps I thought White gets tied up on the queenside.
37...Bxf3
Getting rid of the knight-pair is Black's best option, according to the engines.
38.Kxf3 b4?
The engines give 38...a4 with chances to hold, eg 39.h5 gxh5 40.gxh5 b4 41.Ng4 bxc3 42.bxc3 Ba5 43.Ne3 Kf6 (43...Bxc3?? 44.Nd5+) 44.Ke4 Ke6 45.Nd5 Bd8 46.Ne3 Ba5 47.f5+ Kf7 48.Nd5 Bd8, and it seems difficult for White to make progress.
39.Ke4?!
Blocking the queenside with 39.a4 wins.
39...Bc7?
39...a4 gives similar lines to the note at move 38, again with chances to hold.
40.a4 Ke6 41.h5 gxh5 42.gxh5 b3 43.Nd1 Bd8 44.Ne3 Bf6 45.Nxc4 Kf7 46.Kd5 1-0