8/8/4p3/4P2b/7N/8/5KPp/7k w - - 0 1
8.Nc1 and black is in zugzwang because he can no longer protect the g3 square appropriately, and must give up the h-pawn and the bishop for the knight.
Alena, a bit more convoluted than it needed to be, but you have the right elemental position between moves 10 and and 12. Of course, Dave had found the key element in his comment derived from one of your previous lines. The most concise route is the following:
It's a winning position for white.
Now think about this problem at this stage- white wants to bring the knight to g3 via e4, e2, f1, or h5. Black defends this by covering those squares with the bishop the move before the knight reaches them by staying on the h3/f5 diagonal. You will find that after move 5 (the previous moves in the line) that white can never accomplish this- the bishop has three safe squares on that diagonal, and always two safe moves while on it- that is too much flexibility for the knight to overcome to reach e2, e4, or f1. In addition, the knight can only reach h5 by coming from g3, which is irrelevant, and f6 and g7- but this also fails because black can always put the bishop on f3 safely since white can't let the black king off of h1 when the knight is on f6 or g7. This is why 1.g4 is an error- and that 1.g3 was the right start.
What you need to try to think of is a position where white can let the black king off of the h1 square safely- that is the type of position you are trying to create. What I notice about your problem solving is that you seem to always try a linear approach to them- you start of move 1 and try to work out where to go at each stage. This is perfectly fine a lot of the time, but you should always try to think about what a winning position might be- literally create one out of this problem, for example, then try to work towards that position from move 1.
Ok, I am going to show you a line that demonstrates the problem white has to overcome:
That's how I reached this position yesterday.
And looking at Dave's line, it seems reasonable that 1.Nf1 gets to the right place, too, but in more moves than I had in mind.
I think it can still be won after 8/8/4p3/4P3/6b1/4N1P1/5K1p/7k w, but I have to think about it- I think the continuation would be Nc2 in, but I can't rule out other pathways converging to the winning line. From Nc2, I can, I think see the winning path again. What sequence of moves do you use to get to the position you described?
Alena said: I reached this position which I can't win with my idea 8/8/4p3/4P3/6b1/4N1P1/5K1p/7k w - -.
If there is a mate in 16 after 2.....Bg4, then you found a line I never found, but the most tenacious defense is 2......Bh5.
Alena, 1. Nf1 Bh3 2. Nd2 Bg4 3. Nb1 Bf5 4. Nc3 Bg4 5. Na2 Bd1 6. g4 Bxg4 7. Nc1 Be2 8. Nb3 Bf3 9. Nc5 Bd5 10. Nd3 Bf3 11. Kxf3!! Kg1 12. Nf2! and White can stop Black h-pawn from queening.
I reached this position which I can't win with my idea 8/8/4p3/4P3/6b1/4N1P1/5K1p/7k w - -.
Do you mean 2...Bh5?
Yancey, I tried to play the position with 2...Bg4 and I got mate in16 with the same idea. Can you be more specific?
Alena, you have the start right, but nothing else. In particular, you choose the worse moves for black almost immediately. This much is right 1.g3! Bf3 2.Ng6, but black has two better moves than 2......Bd1. And I will just give you a hint about the end- white doesn't checkmate the cornered king, nor does he queen the g-pawn.
The first move is obvious, but after that it's more difficult. The black king is in prison.The knight can checkmate on g3 or f2.Therefore white has got two threats. They are checkmate and advance g-pawn.Black won't be able to hold the position. I enjoyed this puzzle.