Q: Can White win this position, with White’s turn to play?
With only a King and a Pawn for White and a lone King for Black on the board, you might think there isn’t much you can do.. But then you remember, a Pawn can become a Queen! Especially a pawn like the one on a2 has great potential as it is a Passed pawn.
Passed Pawn must be pushed
Passed Pawn |
A passed pawn is one with no opposing pawns on its way to promotion. It is a potential queen that frequently determines the strategy for both sides: the side with the passed pawn usually aims to promote it, while the opponent must devise a strategy to block or capture it.
With such little material remaining
on the board, calculation and clarity are essential. Timing determines whether one should push the Pawn directly, support its queening square with our King, or block the opponent's King's path.
In this position, White's main strategy is to push the pawn as rapidly as possible to a8 and hope that Black's King doesn't reach the Queenside in time to stop it.
A simple method to find out if White wins is ‘counting’. It takes 5 moves for the White pawn to reach a8. Since Black’s only chance to defend is by bringing his King closer to the a8 square, we can anticipate his answers too: 1.a4 Kf7 2. a5 Ke7 3. a6 Kd7 4. a7 Kc7 (The Black King is too late. He had to reach b7 by this move to control the a8 square) 5. a8 = Queen. White emerges a Queen Up with a winning position. The answer to the question is a resounding YES!
The "Rule of the Square" is another simple and popular method for verifying the efficiency of our passed pawn's straightforward push to the queening square.
Rule of the Square:
Rule of the Square |
Grandmaster Mark Dvoretsky explains the Rule of the Square in his classic book “ The Endgame Manual “ as follows: “ Imagine a Square (he means the geometric shape of a Square) having for one of it’s four sides the path from the pawn to it’s queening square. If the opponent King stands within the Square or can reach within if it were the opponent’s turn to move, then the pawn can be stopped.” In the above diagram, if the Black King were on e7 instead of g7, OR, since it is Black’s turn to play after 1.a4, if the Black King were on f7 with 1…Ke7 here, then Black could stop the pawn with his King. Otherwise, the pawn Queens. By the way, when the pawn stood on a2, since a pawn can move 2 squares on its first move, the square would be constructed from the a3 square, as the pawn would take the same number of moves on the fastest route to a8, whether from a2 or a3.
With White’s turn to play, can White win this position?
Again, by rule of square, or by pure counting, we see that the Black King cannot stop the White Pawn from Queening. But Black now has a passed pawn of his own, on the opposite side of the board!
Pawn Race
Pawn Race |
A pawn race occurs when both sides have passed pawns, and each side rushes to promote their pawn to a Queen. In a pawn race, every tempo (a single move) counts. Again, the king's activity and the pawns' position are critical. For example, a king placed in the centre of the board can quickly support a pawn’s progress or hinder the opponent. The relative speed of the pawns—whether they are blocked by opposing pawns or have a clear path—is a key factor in determining the outcome.
So, is it a draw since both the players can make a Queen at the same time? What do you think?
In fact, White wins! To understand why, let us visualise the position at the end of the first 5 moves, which are obvious: both sides push their pawn forward and make a Queen. The new Queens appear on squares a8 and h1, which we notice are on the same diagonal! This means that the side to move can pick up the opponent’s Queen immediately on the next move. White’s sixth move will be 6. Qh1!
However, if the Black King were on g1, instead of g7, the position would have been completely equal, as the Black King would have supported his Queen on h1 in the end! If the Black King would have been on the Queenside at the start, let's say on a7, then White would have to find the only way to a draw, by entering the ‘Square’ of the h7 pawn on the first move, with 1. Kc2.
We reach g2 on time, just as the Black Pawn arrives on h2. Draw!
