Rich As A King

Saturday, December 14, 2013

A classic brain teaser

White to move. What is the best continuation for White? Is this a draw, win or loss for White?



Manish Shrikhande said...

f7 wins for white.

Ivan Smilianov said...

It's a draw:
1.f7 Rf8 2.e6 b6 3.Kb7 Kc5 4.e7 Rxf7 5.Ka6 Rxe7

Yancey Ward said...

Has to start 1.f7, but I can't find a win for white, though he can draw if he is careful.

Anonymous said...

Truly awesome! 1. f7 Rf8 2. e6 b6 3. Kb7 Kc5 4. e7 Rxf7 5. Ka6 Rxe7 stalemate.

Anonymous said...

the only possible continuation for white seems pawn f7 which is countered by rook f8...and later pawn b6...cant see white winning this one...draw?? if his last name is Carlsen...may be...

shashwat khanna said...

1.f7 1...Rf8
2.e6 2...b6
3.Kb7 3...Kc5
4.e7 4...Rxf7
5.Ka6 5...Rxe7 Stalemate

Anonymous said...

f7 followed by e6 either winning rook or queening a pawn

s.k.srivastava said...

1f7 rf8 2e6 b6 3kb7kc5 4kc7 kd5
5 Kd7 b5 6ke7 rb8 7kf6 wins

Yancey Ward said...

An interesting puzzle. At first glance, it appears that white must either win a queen vs rook ending, or black must win both white pawns and the game as a result- however, the truth is that black wins both white pawns, but white still draws!:

1. f7

The only move to draw of course- otherwise black is going to capture at e6 on white's other legal move and will then win the f-pawn and the game. Continuing:

1. .....Rf8 (the only move)
2. e6

Another obvious only move. Continuing:

2. .....b6!

In my opinion, this is the only interesting thing in this puzzle- but it is black that is fighting to draw. Only b6 prevents white from winning with 3.e7- it allows black to capture at f7 and pinning and winning the e7 pawn. Continuing:

3. Kb7

The only alternative was 3.e7 which loses quickly. Continuing:

3. .....Kc5

Any rook move like Rh8/d8 is going to lose to e7, and Ka5 is going to lose to Kc6 with the unstoppable threat of e7. With 3.Kc5, black is now threatening Kd6 winning the white pawns, and is also threatening b5-b4 etc. Continuing:

4. e7

White has no choice now, but I will cover 4.Kc7 separately below because it is more complex than I want to discuss in a parenthetical sideline. Continuing:

4. .....Rf7

And, for all the world, this looks like a clean win for black, but for one itty bitty detail.....

5. Ka6!! Re7 (this or lose)

And white is stalemated.

At move 4, white cannot win by playing 4.Kc7, and will lose instead:

4. Kc7? Kd5!
5. Kd7

Or [5.e7 Rf7 6.Kd7 Re7! 7.Ke7 b5-+ wins easily for black]. Continuing:

5. .....Ke5!
6. Ke7 Rb8

And now white cannot queen the f-pawn to win the rook without also losing the pawn at e6 in the process, and black will win with the b-pawn. White's most resistant path is to again threaten e7:

7. Kd7 Kf6!
8. e7

No better is attacking the rook: [8.Kc7 Ke6 9.Kb8 Kf7 10.Kb7 b5-+]. Continuing:

8. .....Kf7 and black wins easily from here.

Anand Gautam said...

Aren't there just three legal moves?
Kxb7 & e6 both lose to Rook takes e pawn. So first move has to be
1. f7 Rf8
2. e6 b6! (3. e7?? Rxf7 0-1)
3. Kb7! Kc5 (what else?)
4. Kc7 and White will win...

Lucymarie said...

At first I thought this was a win for White: no way to stop the advanced connected passed pawns. Then I thought it was a win for Black. Finally, I realized that it is a draw.

1. f7 The only move that doesn't lose. Rf8! The only move to hold the game. Looks terrible, putting the rook on a file adjacent to the e-pawn. But the point is that White's king is on the 7th rank, and taking the f-pawn, when the e-pawn is on e7, with a pin becomes a possibility.

2. e6 Again, the only move that holds. b6!

3. Kb7 (3. e7?? Rxf7 wins.) 3. .. Kc5 Threatening to go to d6, and pick up both White pawns.

Here we come to a great parting of the ways. First I will show the wrong way to play it for White.

4. Kc7? This attempt to prevent Black from gobbling up the pawns loses. Kd5 [.. b5?? loses]

5. Kd7 Ke5 6. Ke7

6. e7? Rxf7 wins right away.

6. .. Rb8 The most simple to calculate. .. Rh8, I suspect, wins as well.

7. Kd7 (7. f8=Q Rxf8 8. Kxf8 Kxe6 wins.)
7. .. Kf6 8. Kc7 (8. e7 Kxf7 9. Kc7 b5 10. Kxb8 Kxe7)
8. .. Kxe6 9. Kxb8 Kxf7 and White cannot prevent the b-pawn from becoming a queen. One tempo away.

The correct way for White to play on the 4th move is:

4. e7!! At first, I gave this move a question mark, but later realized that it is the only move to hold the game. White forces Black to carry out his threat of winning both pawns!

4. .. Rxf7 5. Ka6 Rxe7 Otherwise the pawn queens. So stalemate it is.

Lucymarie Ruth