Because with e8, White wastes a tempo. That white pawn is a goner anyway, there is no need for white to spend a move on it. The main point was that White is one move short to be able to get back and stop the black f-pawn from marching up and forcing the promotion of black’s g-pawn. Kc6 forces Black to spend a move capturing the pawn in order to avoid White promoting first, after which White can turn around and stop Black’s f-pawn, having gained a move.
I agree with the first Anonymous. The best White can expect is a draw by 1. Kb5 f5 (else 2. Kc4/3. Kxd3 wins) 2. Kc6 (threatening 3. Kd7, winning) Kxe7 3. Kd5 Kf6 4. Kd4 f4 5. Ke4 Kg5 6. Kf3 Kf5 stalemate.
Any other sequence will lead to a loss because of …f5/…f4/…f3.
Ano 2: 1. e8Q?? or any other king approach that is not forcing black to capture the pawn loses to advance of black’s f pawn to f3.
The clew is that white is one move to slow to stop black’s f (g pawn) but with the Reti maneuver Ka4-b5-c6 both threatening to reach the pawn and to get to d7 he gets the time needed as black has to do the intermediate move Kxe7.
This exercise may even be easier to handle in a real game than here. While here we try to calculate from the starting position if white wins in the end in a real game we can simply play the first moves as it is quick to be seen that nothing else even saves white. So we just play and see the result in the end. 🙂
anonymous, not e8 first, coz white needs to gain a tempo by threatening Kd7. This tempo (forcing black to capture on d7) brings white’s king closer to the f-pawn
Neat site Susan, It’s a draw etc.1.Kb5 f5 2.Kc6 (with the idea Kd7)Kxe7 3.Kd5 Kf6 4.Kd4 f4 ((if 4.__Kg5 5.Kxd3 f4 6.Ke2 Kg4 7.d4 f3+ 8.Kf1 f2 9.d5 Kf5 10.d6 Ke6 11.d7 Kxd7(now whites king goes Ke2-Kf1 with a draw ))5.Ke4 Kg5 6.Kf3 Kf5 (1/2 1/2) etc. Mike R.
Black threatens to advance de f-pawn and Queen on g1 after taking, or simply on f1. The White King cannot come back to defend in time; he is a tempo short. Fortunately, White threatens to Queen of e8, but Black doesn’t have to take the pawn until it has moved, after which White is still a tempo short. So, the White King must threaten to guard the e-pawn while not losing a tempo in order to prevent Black from queening.
The White King will march to b5, c6, (Black must now take the pawn and White gains the needed tempo) d5 and e4
1. Kb5 f5
2. Kc6 kxf7
3. Kd5 kf6
4. Kd4 f4
5. Ke4 with a raid on the chicken coup.
If black tries 1…kxe7 white plays 2 kc4
why not e8 first ?
1. Kb5 f5
2. Kc6 kxf7
3. Kd5 kf6
4. Kd4 f4
5. Ke4 with a raid on the chicken coup.
If black tries 1…kxe7 white plays 2 kc4
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anon 1:06,
Because with e8, White wastes a tempo. That white pawn is a goner anyway, there is no need for white to spend a move on it. The main point was that White is one move short to be able to get back and stop the black f-pawn from marching up and forcing the promotion of black’s g-pawn. Kc6 forces Black to spend a move capturing the pawn in order to avoid White promoting first, after which White can turn around and stop Black’s f-pawn, having gained a move.
Then the black king will take the promoted pawn…
I agree with the first Anonymous. The best White can expect is a draw by 1. Kb5 f5 (else 2. Kc4/3. Kxd3 wins) 2. Kc6 (threatening 3. Kd7, winning) Kxe7 3. Kd5 Kf6 4. Kd4 f4 5. Ke4 Kg5 6. Kf3 Kf5 stalemate.
Any other sequence will lead to a loss because of …f5/…f4/…f3.
Ano 2: 1. e8Q?? or any other king approach that is not forcing black to capture the pawn loses to advance of black’s f pawn to f3.
The clew is that white is one move to slow to stop black’s f (g pawn) but with the Reti maneuver Ka4-b5-c6 both threatening to reach the pawn and to get to d7 he gets the time needed as black has to do the intermediate move Kxe7.
This exercise may even be easier to handle in a real game than here.
While here we try to calculate from the starting position if white wins in the end in a real game we can simply play the first moves as it is quick to be seen that nothing else even saves white. So we just play and see the result in the end. 🙂
Best wishes from Germany
Jochen
1.e8Q+ Kxe8
2.Kb5 f5
3.Kc4 f4
4.Kxd3 f3
Now:
5.gxf3 g2
6.Ke2 g1Q winning
5.Ke2 fxg2 and the pawn will queen.
why not e8 first ?
1.e8Q? Kxe8
2.Kb4 f5
3.Kc4 f4
4.Kxd3 f3 winning for black.
pushing the f-pawn is blacks main threat, so anon #1 is right. White wins a tempo threatening 3.Kd7.
Nice is the end:
1. Kb5 f5
2. Kc6 kxf7
3. Kd5 kf6
4. Kd4 f4
5. Ke4 an now
5. .. Kg5
6. Kf3 Kf5 stalemate!
Tobe
1.Kb5 f5
2.Kc6 Ke7
3.Kd5 Kf6
4.Ke4 Kg5
5.Kf3 Kf5 stalemate
1. Kb5 f5
2. Kc6 kxe7
3. Kd5 kf6
4. Kd4 f4
5. Ke4 Kg5
6. Kf3 Kf5
Stalemate.
Otherwise Black must leave the pawn.
Other white continuations allow f-pawn to reach f3 winning for black
anonymous, not e8 first, coz white needs to gain a tempo by threatening Kd7. This tempo (forcing black to capture on d7) brings white’s king closer to the f-pawn
first anon got it right I think. White has to protect from the ride of f6 pawn
Neat site Susan, It’s a draw etc.1.Kb5 f5 2.Kc6 (with the idea Kd7)Kxe7 3.Kd5 Kf6 4.Kd4 f4 ((if 4.__Kg5 5.Kxd3 f4 6.Ke2 Kg4 7.d4 f3+ 8.Kf1 f2 9.d5 Kf5 10.d6 Ke6 11.d7 Kxd7(now whites king goes Ke2-Kf1 with a draw ))5.Ke4 Kg5 6.Kf3 Kf5 (1/2 1/2) etc. Mike R.
Black threatens to advance de f-pawn and Queen on g1 after taking, or simply on f1. The White King cannot come back to defend in time; he is a tempo short. Fortunately, White threatens to Queen of e8, but Black doesn’t have to take the pawn until it has moved, after which White is still a tempo short. So, the White King must threaten to guard the e-pawn while not losing a tempo in order to prevent Black from queening.
The White King will march to b5, c6, (Black must now take the pawn and White gains the needed tempo) d5 and e4
With normal tactics, B wins.
However the line
1. Kb5 f5
2. Kc6 Kxf7
3. Kd5 Kf6
4. Kd4 f4
5. Ke4 Kg5
6. Kf3 Kf5 Pat
saves W.
Olimat
The saving clause for W is:
1. Kb5 f5
2. Kc6 Kxf7
3. Kd5 Kf6
4. Kd4 f4
5. Ke4 Kg5
6. Kf3 Kf5
PAT!
Olimat
Hmmm. I needed a computer for this…