Here's a Week 3 Ending Puzzle.
This is a fragment of a game between British player Gavin Crawley and Norwegian GM Jon Ludwig Hammer. Hammer won the event (London FIDE Open 2009, that went on concurrently with the London Chess Classic, with a huge score). In fact, he won this ending. As they say, "Fortune favors the brave."
What do you think about the first diagram; what's the result with best play? White win, draw, or Black win?
CORRECT ANSWER: DRAW. White has various ways of either a) getting rid of all the pawns or b) establishing a protected passed pawn on b7, after which there can be no zugzwang - white can just shuttle his king around and black cannot improve his position.
The game continued and reached this position. To give a hint, no mistakes were made between the first and the second diagram! (by either side).
Now what do you think?
STILL A DRAW. White can safely take on b7,
1. cxb7 Kd7 2. Kc5 Bd6+ 3. Kd5 Bg3 4. Kc5 Bf4 5. d5! with a draw.
Or, he can play 1. Kc5 Kc8 2. d5 Be1 3. d6 bxc6 4. Kxc6 Kb8 5. d7 Bh4 with a draw.
And finally we reached this position. Can white save the game at this point?
Is the right move Ke7 or Kc5, or does it not matter? In the game, white chose Ke7.
Ke7? unfortunately lost. The game went on 1. Ke7? Bxa5 2. d6 Bxb6 and white discovered that black will be left with a killer a-pawn.
At this juncture, white can still save it: 1 Kc5! Bxa5 2 d6 Be1 3 d7+ Kd8 4 cxb7 Bg3 and now 5 Kb4! eliminating the last black pawn with Ka5!