Annotations (condensed):

5...Ba5 <...Bc5 also comes into consideration.>

9.e5 <!>

13.Nd2 <Attack at all cost! White proceeds with the courage of a lion.>

14...Qf6 <After 14...g6 15.Rxe5+ Be6 White can continue the attack with 16.Qe2 or Qh3 with good prospects.>

16...Kf8 <? Hoping to find safety on g8 and not sensing White's fantastic combination.> 16...Kd7 is better.

17.Qxe5 <!! A ♕ sacrifice of incredible depth! It has to be examined if the sacrifice can be declined:

I) 17...Bd7 18.Nxf7+ Kg8 19.Nh6# or 18...Bb4 19.Bxb4+ etc.

II) 17...Be6 18.Nxf7+! Kxf7 19.Bxe6+ Ke8 20.Qc7 and wins, or 18...Kg8 19.Nh6+ etc. or 18...Ke8 19.Qd6 Bxe1 20.Bxe6 and wins.

III) 17...Qe6 18.Nf5+ Bb4 19.Bxb4+ Nxb4 20.Bxe6 etc. or 18...Ke8 19.Nxg7+ Kd7 (19...Kd8 20.Nxe6+ followed by 21.Qxh8) 20.Bxe6+ and wins.

So the sacrifice has to be accepted.> While beautiful and advantageous to White, the ♕ sacrifice may not have been White's best and 17.Nxf7+ stronger.

18.Rxe5 <threatens 19.Nxf7 followed by Nh6#, but also 19.Re8#.>

18...Be6 <The position is very complex and White had to calculate extraordinarily deep.

I) 18...Bd7 19.Nxf7+ Kg8 20.Nh6#

II) 18...Qe6 19.Nxc8+ Kg8 20.Ne7+ Qxe7 21.Rxe7 Bxa1 22.Bxf7+ Kf8 23.Rd7# or 19...Ke8 20.Nd6+ Kd8 21.Bxe6 Bxa1 22.Nxf7+ and wins, or 20...Kd7 21.Bxe6+ fxe6 22.Rd1 with winning advantage, or 20...Kf8 21.Nf5+ Kg8 22.Rxe6 Bxa1 23.Re7 Rf8 24.Bxf7+ and wins, or 21...Ke8 22.Nxg7+ Kd7 23.Bxe6+ fxe6 24.Rd1 and wins.>

19.Nc8+ <!! One of the points!>

19...Ke8 <19...Kg8 20.Ne7+ Kf8 21.Nxg6+ Ke8 22.Nxh8 Bxa1 23.Bxe6 fxe6 24.Rxe6+ Kd7 25.Re7+ Kc6 26.Nf7 d3 27.Ne5+! Bxe5 28.Rxe5 d2 29.Rc5+ and wins. Georg Marco disagrees as after ...Re8, Black wins. White has to play better before and he can by 23.Nxf7! Kxf7 24.Rxe6 and wins.> At the end is a note saying that <White announced mate in 4 after 19...Ke8.>

21...Kc7 <Now it becomes obvious that 19.Nc8+ was necessary, to take away b6 from the Black ♔.>