One weakness can usually be defended. Two, far apart, usually cannot. This lesson shows the method strong players use to convert an advantage: tie the opponent’s pieces to the first weakness, open a second front on the other wing, and switch between them until the defence gives way.
In Pro
The Principle of Two Weaknesses is part of Pro, with all 25 lessons and every quiz.
Pro is $6.99 a month or $49 a year. Start free: three days
in a row earns 72 hours of Pro with no card.
An extra pawn rarely wins on its own. It wins when it ties an enemy piece down and you then attack somewhere that piece cannot reach. Chess writers call this the principle of two weaknesses, and it is how most won endgames are actually won.
What you will learn
01Why one weakness can usually be defended and two far apart usually cannot.
02How to tie a defender first, with a rook stuck in front of a passed pawn as the classic case.
03Where to find the second weakness: a pawn break, a king march, or a new target in the centre.
04Why the switch works best slowly, with every piece improved before the break.
Tie, then switch
Two sections show a rook ending. White has a passed pawn on b6 with the rook behind it on b1; Black’s rook blockades on b7 and the king on g7 guards f7, g6 and h6. Then White’s king arrives on f4, with arrows to g5 and e5: against the king side pawns, or across to c7 next to the b-pawn. Black has one king for two jobs. The third section is the middlegame version, the Carlsbad structure after the minority attack, with a backward pawn on c6 and the e3 to e4 break as the second front.
The club mistake is to keep hitting the first weakness. Three attackers against three defenders on a6 or c6 gets nowhere, and the position goes stale. Look at the other wing instead and ask which squares the tied pieces can no longer reach.
How to practise it
Two quiz positions, both rook endings. In the first, White keeps the passed a-pawn so that Black’s rook stays tied; in the second, White opens the second front. One move each, by voice or tap. This lesson is in Pro.
Against good defence one weakness is rarely enough to win. Create a second one far from the first, and the defender cannot cover both with the same pieces.
Does it only apply to endgames?
No. It is clearest in endgames, but the same idea runs through the minority attack and most long middlegame squeezes: fix one target, then attack on the other wing.