Finding the Critical Move

In The Most Infamous World Championship Game, I noted two controversies associated with that game. If we accept the logical resolution of the first controversy: that Schlechter needed to win the match by one game, not two, the second controversy remains: how or why did he lose the game when he had draw, match, and title in hand?

Every good chess game, meaning every game that represents a real fight, contains a number of positions which are more important than other positions. These are potential turning points where a good move maintains the logic of the position and a poor move loses. This is sometimes called the Critical Move. The higher up the Elo food chain, the faster a player finds these moves.

In most well annotated games, the position(s) with the critical moves jumps at you. In the games discussed so far in this series on Lasker's Moves that Matter, I was able to identify those positions after playing through the game a few times. When I look at the tenth game of the Lasker - Schlechter match, many positions are candidates for critical moves.

To gain insight into this game, I enlisted the support of the two annotators who have been helping me understand the games, Kasparov (GK) and Soltis (AS), and added a third GM player/historian, Ludek Pachman (LP), who included the game in his classic 'Decisive Games in Chess History'. I collated the symbols they assigned to each move (!, ?, etc.) into a side by side comparison and produced the following PGN file...

[Event "Ch World (match)"]
[Site "Berlin/Vienna"]
[Date "1910.??.??"]
[Round "10"]
[White "Lasker Emanuel"]
[Black "Schlechter Carl"]
[Result "1-0"]
[ECO "D94"]

1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.e3 g6 {GK:!?} 5.Nc3 Bg7 6.Bd3 O-O 7.Qc2 {GK:?!} Na6 {AS:!? LP:(?)} 8.a3 dxc4 {GK:?!} 9.Bxc4 b5 {GK:?} 10.Bd3 b4 {GK:?!} 11.Na4 {AS:!} bxa3 12.bxa3 Bb7 13.Rb1 Qc7 14. Ne5 {LP:!?} Nh5 15.g4 {GK:? LP:!?} Bxe5 {GK:?} 16.gxh5 {GK:! LP:! } Bg7 17.hxg6 hxg6 18.Qc4 {GK:! AS:!} Bc8 {GK:!} 19.Rg1 {GK:?!} Qa5+ {AS:!} 20.Bd2 Qd5 21.Rc1 {AS:!} Bb7 22.Qc2 {GK:!?} Qh5 23.Bxg6 {GK:? AS:? LP:!?} Qxh2 {GK:!} 24.Rf1 fxg6 25.Qb3+ Rf7 26. Qxb7 Raf8 {GK:! AS:! LP:!} 27.Qb3 {LP:?} Kh8 28.f4 g5 {GK:!? AS:! LP:!} 29.Qd3 gxf4 {AS:! LP:!} 30.exf4 Qh4+ 31.Ke2 {AS:!} Qh2+ 32.Rf2 Qh5+ 33.Rf3 Nc7 {GK:! AS:! LP:!} 34.Rxc6 {GK:?! AS:? } Nb5 {GK:! AS:! LP:!} 35.Rc4 {GK:!} Rxf4 {GK:? AS:? LP:?} 36. Bxf4 Rxf4 37.Rc8+ Bf8 38.Kf2 {GK:! AS:!} Qh2+ {LP:!} 39.Ke1 Qh1+ {GK:? AS:? LP:?} 40.Rf1 Qh4+ 41.Kd2 Rxf1 42.Qxf1 Qxd4+ 43.Qd3 Qf2+ 44.Kd1 Nd6 45.Rc5 Bh6 46.Rd5 Kg8 47.Nc5 Qg1+ 48.Kc2 Qc1+ 49.Kb3 Bg7 50.Ne6 { GK:?!} Qb2+ {GK:?} 51.Ka4 Kf7 {GK:? AS:?} 52.Nxg7 Qxg7 53.Qb3 { LP:!} Ke8 54.Qb8+ Kf7 55.Qxa7 Qg4+ 56.Qd4 Qd7+ 57.Kb3 Qb7+ 58.Ka2 Qc6 59.Qd3 Ke6 60.Rg5 Kd7 61.Re5 Qg2+ 62.Re2 Qg4 63.Rd2 Qa4 64.Qf5+ Kc7 {GK:?!} 65.Qc2+ Qxc2+ 66.Rxc2+ Kb6 67.Re2 Nc8 68.Kb3 Kc6 69.Rc2+ Kb7 70.Kb4 Na7 71.Kc5 1-0

...The first glance indicates the critical moves: 23.Bxg6 {GK:? AS:? LP:!?}, 26...Raf8 {GK:! AS:! LP:!}, 28...g5 {GK:!? AS:! LP:!}, 33...Nc7 {GK:! AS:! LP:!}, 34...Nb5 {GK:! AS:! LP:!}, 35...Rxf4 {GK:? AS:? LP:?}, and 39...Qh1+ {GK:? AS:? LP:?}. All but one were played by Schlechter. What will further analysis tell me?