1

Georg Mohr:

The principle of the second
weakness

The theory about the play in endgames is
often divided into several parts. Theoretical
endgames

are

fundamental

for

our

knowledge, because we need to memorize
many different positions and understand them.
The number of that kind of endgames is
growing day after day. Without that basic
knowledge we cannot play good in endgames.
Practical endgames are the second area,
where it is important to understand certain
positions. There are not many positions in the
middlegame, that can transpose directly into a
theoretical

endgame. In the beginning

endgames are usually complicated, but then
they can be drawn into theoretical positions.
But if we want to play them good, it is
necessary to know some principles: these
principles are especially meant for the
endgames that are not theoretical. One of
these principles is the principle of the second
weakness, which is mentioned in every good
chess book. The principle of the second
weakness is one of the most important parts of
realization of advantage in the endgames
(Dvoretsky). The great Russian trainer
described: ”When the opponent is in a passive
position, you have to attack different
weaknesses. If you attack only one weakness,
the player will be able to defend himself. It is
necessary to attack other weaknesses. In most
of the case we need to create the second
weakness.”

Let’s look how this principle was used by the
great chess masters in the past. For the
beginning, let’s look the (sad) example of the
greatest Slovenian grandmaster dr. Milan
Vidmar. This year we are celebrating his
125th birth anniversary (ECU declared the
year of 2010 as Vidmar’s year).

Flohr, Salo : dr. Vidmar, Milan,
Nottingham, 1936

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White has an advantage, but Black could
easily equalize due to possible inaccurate play
of White. He just needs a move or two to
bring his King into the center and so defend
the d5 Pawn , which is his only weakness.
How should White continue?
Flohr understood, that the d5 weakness is not
going to be enough for him to win the game.
That is why he wonderfully created the second
weakness and so pushed the black King and
Rook into defense.
1.Nc6! Rc8 2.Rc5
It would be better to play 2.Ke2, because
black cannot enter into the pawn endgame
2...Rc6: 3.Rc6 bc6 4.b4 Ke7 5.Kd3 Kd6
6.Kd4 and White should win. 2...bc6 3.Rc5
and the position is like in the game.
2...bc6?
Dr. Vidmar would definitely defend himself
better after 2...Rc6 3.Rd5 Rc2. With a move
less a pawn ending is also a draw, after 3.Rc6
bc6 4.b4 Ke7 5.Ke2 Kd6 6.Kd3 c5.
3.Ke2
The rule says: »Don’t rush!« After the
inpatient 3.Ra5, Black would activate himself:
3...c5! 4.Ra6 c4!, with good chances for draw.
That is why we need to centralize the King
first and only then we activate the Rook.
3...Ke7 4.Kd3 Kd6 5.Ra5
The art of realization of advantage is in the
endgame directly connected with small

2

tactical operations. So, it was bad 5.Kd4?
Rb8! 6.Ra5 c5! 7.Kd3 (7.Rc5?? Rb4) 7...Rb6.
5...Ra8 6.Kd4

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A total domination! Black Rook has only two
squares (a8 and a7) and black King cannot
move, because he would let White King on c5
or e5. But this is not enough for White to win
the game. He needs to create the second
weakness. Only after that Black will not be
able to defend. It is clear that White will need
to create the second weakness on the King’s
side. Let see how Flohr handled the situation.
First he slowly improved the position on the
Queen’s side and then he started with
activities in the centre and on the King’s side.
6...f5
Dr. Vidmar understood that e3-e4 move will
be decisive and he wanted to exchange as
many Pawns as possible on the critical e4
square (usually exchanges are in favor for the
defending side)
7.b4! Rb8?!
Dvoretsky proved in his books, that Black
should defend with an active play. That means
with the plan: King goes to b7 (and let’s white
King in), Rook goes to e-semi open file,
which would later, potentially, be opened with
a Pawn sacrifice (f4 or d4).
8.a3!
Move slowly!
8...Ra8 9.e4!
White cannot improve his position and it is
time to create the second weakness on the

King’s side. Black has no choice and he is
forced to exchange in the centre.
9...fe4 10.fe4 de4 11.Ke4

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The

next

critical

moment:

White

is

threatening with the penetration of the King.
The most appropriate defense in similar
positions is an active defense – so Black must
free his Rook. We already know the principle:
King on c7, Rook on an open file. So
11...Kc7!, 12...Kb6 and check with the Rook
on e8 or f8.
11...Ra7?! 12.Kf4 h6
If not, King penetrates on h6 with a decisive
affect: 12...Ra8 13.Kg5 Ra7 14.Kh6 Ke6
15.g4, with the idea h4-h5 +- (Dvoretsky).
13.h4 Ke6 14.Kg4 Ra8 15.h5! g5
White created and fixed down a new
weakness – Pawn on h6. Next follows a
combined attack on both wings.
16.g3!
The King is returning to the center. The
played move is excellent. White needs to be
careful, after 16.Kf3 Rf8! 17.Ke4 Rf4 Black
could return into play.
16...Ra7 17.Kf3 Ra8 18.Ke4 Ra7 19.Kd4
Kd6 20.Ke4 Ke6

3

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Next follows a finishing maneuver. After the
next move Black will be lost: after a check
with the Rook, Black has two squares to move
to, but they will not stop White from winning
the game.
21.Re5! Kd6
After 21...Kf6 22.Rc5! Rc7 23.Ra5! Ra7
24.Kd4 and Kc5.
22.Re8 c5
Pawn ending, after 22...Re7 23.Re7 Ke7
24.Ke5 is hopeless. Black cannot save
himself, not even with the c6-c5 move, with
which he wanted to get rid of one of his
weaknesses.
23.Rd8! Kc6
King could not step onto the seventh rank,
because of the transposition to the pawn
endgame: 23...Kc7 24.Rh8 cb4 25.Rh7 Kb8
26.Ra7 Ka7 27.ab4, then a King goes to pick
up the h6 Pawn and White is faster. The rest
of the game is all about the technique.
24.Rc8 Kb6 25.Rc5 Rh7 26.Re5 Kc6 27.Re6
Kb5 28.Kf5 Rf7 29.Rf6 1:0.


Let us look into one modern game – a twin
example!

Nikolic, Predrag : Movsesian, Sergei
Polanica Zdroj, 1996

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The story is very similar to the last one: Black
Rook and King need to wait, but that is still
not enough to win. It is necessary to create the
second weakness in the Kings’ side.
1.Ra5 Ra7 2.g4! h6
2...c5? 3.Kd3 Kc6 4.Kc4+- (Stohl).
3.h4 Ra8
3...f5? 4.gf5 gf5 5.f4+-.
4.b4 Ra7 5.a3
Predrag Nikolić knew the game Flohr :
Vidmar - the principle is the same!
5...Ra8 6.Kd3 Ra7 7.e3 Ra8 8.f4! ef4 9.ef4
Kc7

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Also in this game Black decided for a passive
defense, which cannot bring any success.

4

10.h5! gh5
After 10...g5 11.Ke4 white King moves
forward across f5 and g6. Now it’s too late for
an active counter play: 11...Rg8 12.Ra6 gh5
13.gh5 Rg4 14.Ke4+-.
11.Rh5 Rg8 12.Rh4!
It would be worse to play 12.Rh6 Rg4 13.Rf6
Rg3 and an endgame is close to draw. The
Rook on h4 is passive, but only temporarily,
because the King is no it’s way to support it.
12...Kd7?!
Black would have more chances, after a more
active move 12...f5!?
13.Ke4 Ke6 14.Kf3 Rh8 15.Rh5 Rh7 16.Kg3
The idea is clear: Rook needs to get to c5,
where it would pin Black. The King needs to
move to h5, from where it would be able to
attack the created weakness on h6. Black will
soon not have any space left.
16...Rd7
Black is trying to activate, but White will not
let go. A Pawn can wait.

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17.Ra5! Ra7 18.Kh4 Kf7 19.Kh5 Kg7 20.f5
Kh7
20...Kf7 21.Rc5! Rc7 22.a4 and 23.b5 +-.
21.Rc5 Rc7 22.a4 Kg7
Or 22...Rb7 23.Rc6 Rb4 24.Rf6 and White
wins easily.
23.b5 ab5 24.ab5 Rb7 25.bc6 Rc7 26.Rc1
Rc8 27.c7 Kf7 28.Rc6 Kg7 29.Kh4 Kf7
30.Kg3 1:0.

Anyone that at any time studied the Carlsbad
structure came across the next example:

Kotov, Alexander : Pachman, Ludek
Venice, 1950

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On the diagram White has a brilliant position:
he brought out the maximum of the minority
attack. The weakness is eternal: it is clear that
Black is not threatening with the move c6-c5,
because of d4-c5 and Ra5 and the d5 Pawn is
lost. But only one weakness is not enough to
win: White needs to create another weakness
and an opportunity lies on the King’s side.
1.g4!
That is a very important move that needs to be
remembered. White fixed down the h Pawn
and made it weak. White Rook will be able to
attack it at any time and a black King will
have to defend it. Remember: In this kind of
position Black must play h7-h5, because if he
does not play the move, White will take his
chance and play g2-g4!
1...Ke6 2.Kg2 Rb7 3.Re8
The slow play, full of maneuvers is starting.
White is improving his pieces and he is
weakening Black’s.
3...Re7 4.Rh8 f6
Black did not have a choice, the Pawn on f6 is
not weak yet, but it could become, if black
King moves to far into the Queen’s side.
5.h4 Rb7 6.Kf3 Rf7 7.Re8 Re7 8.Rd8

5

White is preparing the move Nc5. After the
taking, the Rd6 threat will appear. Black Rook
will be chained to the c6 Pawn and it will
need to defend it.
8...Ra7 9.Nc5 Ke7

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10.Rc8!
Accuracy is necessary – White needs to get
the black King away, for another file, from the
Pawns on the King’s side. After the impatient
move, 10.Rh8 Bc5 11.dc5 Ra5 12.Rh7 Kf8,
Black would defend his Paws successfully.
10...Bc5 11.dc5 Kd7 12.Rh8!
After the “zwischenzug” (in-between move),
Black cannot move to the decisive f8 square.
After 12...Ra5 13.Rh7 Ke6 14.Rg7 White
should win the game.
12...Ke6 13.Rd8!
With the maneuvering White reached his goal:
He brought Black into the position that is very
hard to defend. Rook will move to d6 and
Black Rook will be forced to move into a
passive defense.
13...Ke7
Later on some analysis appeared (Speelman),
which are in favor for the move 13...Rc7 and
after 14.Rd6 Ke5, with a more active defense
and with more chances for a draw.
14.Rd6 Ra6

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15.g5!
An instructive maneuver – White is making
the way for the penetration of his King across
the e5 square.
15...fg5 16.hg5 Kf7 17.Kg3 Ke7 18.f3
White needs to be careful: he can penetrate
with his King across the fourth rank, only
after the e4 square will be defended.
Otherwise Black will have a chance for a
counter play with check, firstly on a4 and
secondly on e4.
18...Ra3 19.Kf4 Ra4 20.Ke5 Ra3
This counter play is Black’s only hope. Next
follows the transposition to an endgame with a
Pawn less, but with a reduced material.
21.Rc6 Re3 22.Kd5 Rd3 23.Ke4 Rc3 24.f4
Rc1 25.Rc7 Kd8
After the “mean” 25...Ke6 White should be
keeping an eye on the famous trick: 26.Rh7
Rc4 27.Kf3 Rc5 28.Rg7 Rc6! 70.Rg6 Kf5
71.Rc6 stalemate! The solution is hiding in
the next move 26.Rc6 and with crossing the
King on the Queen’s side.
26.Rh7 Rc5 27.Rf7 1:0.

Conclusion:
The principle of the second weakness is one
of the most important parts of realization
of advantage in the endgames. When the
opponent is in a passive position, you have
to attack different weaknesses. Attacking
only one weakness would not be enough - ,
the player will be able to defend himself.