Aug-09-09
 | | Peligroso Patzer: This is a wonderfully instructive endgame, albeit not so much as played, but rather due to the analysis of the position after 55. ... a5: 
click for larger viewwhere Euwe played 56. e6? (instead of the correct 56. Kb3!, as subsequently analyzed by Euwe and also Alekhine), which text move (56. e6?) Alekhine called "equivalent to proposing a draw" in the tournament book (“Nottingham 1936”, by Alekhine, Alexander, Russell Enterprises, Inc. ©2009, at page 178). The following position:
click for larger viewarises after 64. Kb1 (and thus with BLACK TO MOVE) in the analysis by Euwe posted above by <Calli>, which goes: 56.Kb3! Kb5 57.e6! a4+ 58.Kc2 Ng6 59.h7 Kc6 60.Bf6 Kd6 61.e7 Kd7 62.e5 c4 63.e6+ Ke8 64.Kb1. (See diagram above.) Due to the very important principle that <three connected passed pawns abreast on their fifth rank (the algebraic 4th rank in the case of Black pawns) can be restrained (and actually captured by force when the side with the pawns has no viable move with any other piece or pawn) by a defending King positioned (WHEN THE SIDE WITH SUCH PAWNS IS ON MOVE) on the promotion square of the middle of said three pawns> [Alekhine in the tournament book calls this "the classical position in which the king stops the three passed pawns", ibid. at page 178.], the position in the second of the two diagrams given hereinabove leaves Black in zugzwang. If this is not immediately apparent, it becomes clear after the following additional moves from the Euwe analysis: 64. …c3 65. Kc2! a3 66. Kb3! The same position, but with WHITE TO MOVE, arises after the following analysis variation given by Alekhine in the tournament book (ibid., at page 178): 56.Kb3! Kb5 57.e6! a4+ 58.Ka2 (departing from Euwe’s variation, which gives 58. Kc2) Ng6 59.h7 Kc6 60.e7 Kd7 61.Bf6 c4 62.Kb1 Ke8 63.e5 Kf7 64.e6+ Ke8. The following additional moves from the Alekhine analysis illustrate a second very important endgame principle, specifically that one of the advantages of Bishop versus Knight is <the capacity of the Bishop to “lose a move” or "give the move" to the opponent> by returning to the same square after three moves whilst the Knight moves twice, thus placing Black in zugzwang: 65.Bg5 Nh8 66.Bh4 Ng6 67.Bf6 "and wins" (Alekhine). |
Aug-09-09
| | Peligroso Patzer: To elaborate a little on the “classical position” (as termed by Alekhine; see my previous post) of King defending against three connected passed pawns abreast on the fifth rank (algebraic 4th for Black pawns), the following position is winning for whichever side is on move: 
click for larger viewSpecifically, 1. Kb1! wins for White; or with Black to move, 1. … b3! is  . By contrast, the position: 
click for larger view is winning for Black whoever is on move. If Black is on move, 1. …. b3! wins as in the first position. If White is on move, he can temporarily get the “classical position” with 1. Kb1!, but Black simply plays 1. … Kf7! and puts White in zugzwang (for example, 2. Kc2 c3! .). |
Kibitzing
