Black to move
26...Qd1+ 27.Qxd1+ Rxd1 28.Kf2 Rd2+
The fork
29.Ke3 Rxb2 30.Ra4 a5 31.Ra3 Rxh2
White to move
With a two pawn advantage, Black went on to win.
I used the Manoeuvres search tab in ChessBase to find some training positions with hopes that my students could learn to play similar positions easily. My search was not narrow enough and I had to go through a hundred games to find a few of the sort that I sought. But other tactics emerged in this batch of games as well, and I filed away several positions.
This position from Euwe,M. -- Kroone,G., Amsterdam 1919 is simple enough.
White to move
32.Rc8+ Kg7 33.Rc7+ Kg6 34.Rxb7
White has restored the material balance and has healthier pawns and an active king. The effort to create threats and counterplay led Black to reduce his own rook's mobility and White won. Whether White already has a clear advantage, however, is less clear. The ending may prove instructive for my students. In particular, it was from this position that Stockfish evaluated the game as going from an advantage for White to a decisive advantage.
Black to move
Black played 38...a2. The engine sees Black holding after 38...Ra2.
White more clearly gains a decisive advantage with the maneuver in Zukertort,J. -- Pitschel,K., Paris 1878. This game also featured a queen exchange to simplify matters, as in my game.
White to move
34.Rc8+ Kg7 (other moves lead to a quick checkmate and another elementary lesson for my students.
35.Qg3+Qxg3 36.Kxg3
Black to move
36...Rc1
And now the fork on the seventh. White won the rook ending easily, or so it seemed.
37.Rc7+ Kf6 38.Rxa7 Rxc2 39.Rd7 Rxc3+ 40.Kh4 e4
Black also has a passed pawn.
41.Rxd6+ Ke5
White to move
42.Rxb6?
White let Black back into the game, but nonetheless went on to win. The lessons from this point in the game are for another day.