Zugger zugged

The German expression zugzwang means ‘compulsion to move’ and is most often seen in the endgame. Consider the following position on Diagram 1.
 
It is Black to move. If Black were not obliged to move he could draw by waiting for White to play 1 c7+ Kc8 2 Kc6 with a draw by stalemate. Instead Black is compelled to move, thus losing after 1 … Kc8 2 c7 Kb7 3 Kd7 winning by pawn promotion to queen or even rook.
 
The most famous zugzwang occurred in this week’s game, a classic, where the great Aron Nimzowitsch reduced his opponent to an utter paralysis on a board full of pieces. Notes based on those by Garry Kasparov in his My Great Predecessors series (Everyman Chess).
 
The puzzle this week shows the tables turned with an even greater player, Alexander Alekhine, snaring Nimzowitsch in another lethal middle-game zugzwang.
 
Saemisch-Nimzowitsch: Copenhagen 1923; Queen’s Indian Defence
 
1 d4 Nf6 2 c4 e6 3 Nf3 b6 4 g3 Bb7 5 Bg2 Be7 6 Nc3 0-0 The main move is 6 … Ne4! 7 0-0 d5 8 Ne5 c6 Stronger is 8 … Na6. 9 cxd5 9 e4! is more energetic.White waits with this until move 20 when it is a sign of desperation rather than a seizure of the initiative. 9 … cxd5 10 Bf4 a6 11 Rc1 b5 12 Qb3 Nc6 13 Nxc6 The strong tactical blow 13 Nxd5!, opening the position to White’s advantage, went unnoticed. 13 … Bxc6 14 h3 Qd7 15 Kh2 Saemisch does not seem to know what to do. 15 … Nh5 16 Bd2 f5 17 Qd1 Although White has lost a lot of time, after 17 Nb1 he could still have put up a fight. 17 … b4 18 Nb1 Bb5 19 Rg1 Or 19 Qe1 a5 20 a3 Rab8. ‘One senses how White is shrivelling.’ – Nimzowitsch. 19 … Bd6 20 e4
 
A desperate chance, the only one to try and escape from the vice. 20 … fxe4 An absolutely correct piece sacrifice, leading to the complete paralysis of White’s army. 21 Qxh5 Rxf2 22 Qg5 Raf8 23 Kh1 R8f5 24 Qe3 Bd3 Black is playing for a spectacular zugzwang, but it is even simpler to win the queen: 24 … Re2! 25 Qb3 Ba4 26 Rc8+ Rf8. 25 Rce1 h6!! (see diagram 3)
 
White resigns Brilliant! White has no moves: if 26 Kh2 or 26 g4, then 26 … R5f3!