UMBC, room ECS 023, 3-10-99

Notes by David Joyner. (No claim to completeness.)

**Theme**: Geometry of the chessboard – dynamic case case. Passed pawns.

A **passed pawn** is a pawn which has no opponent pawns on its file nor on any adjacent file between its square and its promotion square. Passed pawns are the top priority in almost every pawn endgame.

A passed pawn is called

**protected**, if it is protected by another pawn;**outside**, if it is located on either flank (i.e., the*a, b g*, or*h*files);**central**, if it is not an outside passed pawn.

The **square of the passed pawn** is the square on the (extended) chessboard whose diagonal runs from the square of the pawn to the promotion rank on the side of the opponent’s king. Noteworthy exceptions:

- Passed rook pawns can only have a square on one side of the file.
- The square of the passed pawn is not always a perfect square on the actual chessboard because of the limitations of the size of the actual board. For example, for a white passed pawn on b5 and the black king on a7, the “square” would be a rectangle having vertices on a5, b5, b8, a8.
- For a pawn on its initial square (2nd rank for white, 7th rank for black) the square of the pawn is the same as if it were on the next rank (3rd rank for white, 6th rank for black).

**Rule of the pawn square**: If the king can step into the square of the passed pawn then the passed pawn can be intercepted. Otherwise, the passed pawn will queen without interception.

In Forsyth notation:

8/5k2/8/1P6/8/8/8/1K6

**White to move and win. Black to move and draw. **

The black king is outside the square of the b5 pawn, so white to move wins by the rule of the pawn square.

**Position 6.2**:

In Forsyth notation:

8/8/3k4/1p1p4/1P5P/4K3/8/8

**White to move and win. **

This relatively trivial example illustrates the idea that in spite of a material advantage, an outside passed pawn is a strong advantage.

**Position 6.3**: From Lombardy-Fischer, Ch USA, 1960/61.

In Forsyth notation:

8/pp4pp/4k3/3rPp2/1Pr4P/2B2PP1/1P2K3/4R3

**Black to play and win. **

1 … Rxc3! 2 bxc3 Rxe5 3 Kd2 Rxe1 4 Kxe1 Kd5 5 Kd2 Kc4 6 h5 b6 7 Kc2 g5! 8 h6 f4 9 g4 a5 10 bxa5 bxa5 and black wins.

In Forsyth notation:

8/8/2k5/8/5pP1/5P2/2K5/8

**Black to play and draw. **

Surprisingly enough, the strong white advantage in this position (up by a protected passed pawn) is not enough to win. Black can draw by using coordination of squares (opposition) to repel the enemy king. 1 … Kd6! 2 Kd2 Kc6! 3 Ke2 Kd6 4 Kd3 Kd5 5 g5 Ke5 6 g6 Kf6 7 Ke4 Kxg6 8 Kxf4 Kf6 and black draws (see basic endgame position 3). White cannot penetrate down the h-file either, since black can defend so that when white plays Kh3, black plays the repelling move Kg5. Note that if the position were only slightly different: all the pawns are move back by one rank (to f4, g5, f5) then black *loses *since the “saving move” … Kc6 doesn’t work in this case (it moves black outside the square of the passed pawn at g5).

**Position 6.5**: From Shaitar-Thelen, Ostrava 1946. This position illustrates how tricky a win can be, despite having a protected passed pawn.

In Forsyth notation:

2k5/2p5/3p4/2PPpK2/8/8/P7/8

**Black to move and win. **

1 … Kb7 2 a3! (2 a4? loses to 2 … dxc5 3 Kxe5 Ka6 4 Ke4 Ka5 5 Kd3 Kb4 etc.) Ka6 3 c6 (if 3 a4?

then 3 … dxc5 and black wins) Kb6! (The move 3 … Ka5 allows the following miracle: 4 Ke6 e4 5 Kd7 Kb6 6 a4 e3 7 a5+ Kc5 8 Kxc7 e2 9 Kd7 Kxd5 10 c7 e1=Q 11 c8=Q Qe6+ 12 Kc7 Qxc8+

13 Kxc8 Kc6 14 Kb8! Kb5 15 Kb7! and draws.) 4 a4 Kc5!! 5 Ke6 e4 6 Kd7 e3 7 Kxc7 e2 8 Kd7 e1=Q 9 c7 Kxd5 10 c8=Q Qe6+ 11 Kd8 Qxc8+ 12 Kxc8 Kc6! 13 a5 d5 and black wins. 4 a4 Kc5 5 Ke6 e4 6 Kd7 e3 7 Kxc7 e2 8 Kd7 e1=Q 9 c7 Kxd5 10 c8=Q Qe6+ 11 Kc7 Qxc8+ 12 Kxc8 Kc6! and black wins.

**Position 6.6**: From Nimzovitch-Tarrash, San Sabastian 1911.

This position illustrates the technique of *separation *where one side prevents the other from creating a protected passed pawn.

In Forsyth notation:

8/5k2/p4p2/5K2/7P/8/6P1/8

**Black to play and win. **

1 … a5 2 Ke4 f5+! 3 Kd4 (white cannot take the pawn, due to the rule of the pawn square) f4! (not allowing white to create a *protected* passed pawn) and black wins.

**Position 6.7**: From E. Geller-R. Fischer, Capablanca Memorial, Havana, 1965. This position also illustrates the technique of separation.

In Forsyth notation:

8/1b6/1P1k2p1/8/5P1p/4Q3/1q2B1PK/8

**White to play and win. **

1 Bf3 Bxf3 2 Qe5+! Qxe5 3 fxe5+ Kxe5 4 gxf3 Kd6 5 f4! (not allowing black to create a protected pawn) and black resigned in the face of 5 … Kc6 7 Kh3 Kb6 8 Kxh4 Kc6 9 Kg5 Kd7 10 Kxg6.

## Homework

Solve the following problems.

**Position 6.8**: This homework problem is from Speilmann-Makarchik, 1939.In Forsyth notation:8/8/8/5k2/6pP/6P1/5K2/8

**Black to play and draw.**solution below

**Position 6.9**:In Forsyth notation:8/8/p3p3/4k1p1/1P2p1Pp/P3K2P/8/8

**White to play and win.**solution below

**Position 6.10**: This homework problem is from Schlechter-Tartakover, 1907.In Forsyth notation:8/1p3pk1/p3p2p/4P1p1/5P2/P7/1P2K1PP/8

**White to play and win.**solution below

**Position 6.11**: This homework problem is a study by Seleznev.In Forsyth notation:8/8/8/8/2pk2p1/P7/1P6/4K3

**White to play and draw.**solution below

**Position 6.12**: In Forsyth notation:8/2k5/6p1/2P1p2p/1K5P/6P1/8/8

**White to play and win.**solution below

**Position 6.13**: This homework problem is a study of Kling and Horwitz (or Gorvitz).In Forsyth notation:8/8/8/2p5/2Pp4/3K2Pk/7P/8

**White to play and win.**solution below

**Position 6.14**: In Forsyth notation:8/8/2p2k2/pp3Pp1/6P1/1KP5/P7/8

**White to move and win. Black to move and draw.**solution below

Homework solutions:

- 1 … Kf6 2 Ke3 Ke5 3 Kd3 (3 h5 draws – see basic endgame position 3) Kd5 4 Kc3 Ke5! 5 Kc4 Ke4! draw.
- 1 a4 … 2 b5 axb5 3 axb5 and white wins because white’s outside passed pawn deflects the black king and allows the white king to penetrate and mop up black’s pawns.
- 1 fxg5 hxg5 2 Kf3 Kg6 3 Kg4 f5+ 4 exf6ep Kxf6 5 g3 e5 6 h4 and white creates and outside passed pawn. This passed pawn can be used to deflect the black king to the h-file, allowing the white king to mop up blacks other pawns.
- 1 Kf2 Kc5 (1 … Kd6 2 a4 Kc7 3 a5 leads to a draw since white queens first and can obtain either a perpetual check or trade queens and then capture the g4 pawn) 2 Kg3 Kb5 3 Kxg4 Ka4 4 Kf5! (the only move which draws!) Kb3 5 a4! (winning a tempo) Kxa4

6 Ke4 Kb3 7 Kd4 draw. - White’s “outside” passed pawn and better king position wins. 1 Kc3! e4 (1 … Kc6 2 Kc4) 2 Kd4 Kc6 3 Kxe4 Kxc5 4 Kf4 and white wins.
- 1 Ke4 Kg4 2 h4 Kh5 3 Kf4 Kg6 4 g4 Kh6 5 h5 Kh7 6 g5 Kg7 7 g6! (7 h6? Kg6 draw.) Kh6 8 Kg4 Kg7 9 Kg5 d3 10 h6+ Kg8 11 Kf6 d2 12 h7+ with mate to follow in a few moves.
*White to move*: 1 a4 Ke5 (1 … bxa4 leaves black’s queenside pawns too weak) 2 axb5 cxb5 3 c4 b4 4 c5 and white wins.*Black to move*: 1 … c5 2 a3 Ke5 3 Kc2 Kd5 4 Kd3 Ke5 and it’s a draw since white can’t penetrate. Note that black should not play … a4 or … c4 since this would weaken the queenside pawns too much.