The Principle of Two Weaknesses: Botvinnik's Textbook Win, Checked

Part 1Sverdlovsk 1943: Botvinnik returns to the board

In the spring of 1943, in the middle of the Second World War, eight of the strongest Soviet players met in Sverdlovsk (now Yekaterinburg) for a double round robin, played from 20 April to 16 May. Mikhail Botvinnik won it, ahead of Vladimir Makogonov, Vasily Smyslov and Isaac Boleslavsky. ^[4][5] ✓ Verified

It was Botvinnik's first tournament after two years away from competitive chess, spent working as an electrical engineer during the war. Botvinnik scored one and a half points out of two against each of the seven other players. Five years later Botvinnik became world champion. ^[3] ✓ Verified

Evgeny Zagoriansky finished near the bottom of the table, with four points from fourteen games. The game between them is not one of Botvinnik's famous attacks. It became famous later, in coaching books and courses, as one of the clearest demonstrations of the principle of two weaknesses: a small, permanent advantage turned into a win by opening a second front. ^[2][6] ✓ Verified

Part 2What is the principle of two weaknesses in chess?

The principle of two weaknesses says that a single weakness can usually be defended, because the defender can bring as many pieces to it as the attacker brings against it. To win, the stronger side creates a second weakness far from the first, often on the other wing or around the king, and switches between the two faster than the defender's pieces can follow.

One sick pawn can lose you the game, but you need two points of attack to win.

The plan runs in stages. First fix the weakness so it cannot advance or be traded. Then attack it with as many pieces as possible, not to win it at once but to tie the defender's pieces to it. Then open the second front, using the extra freedom your pieces have and the opponent's pieces do not. ◐ Inferred

The principle works when the stronger side has more space or more mobile pieces, so that it can switch fronts faster. It does not work when the defender has active counterplay of their own: then the 'second front' only gives the opponent time. ◐ Inferred

Part 3The opening: how an English became an isolated pawn

Botvinnik opened with 1.Nf3 and 2.c4 and put the bishop on b2, a quiet English Opening setup. Black chose a solid Queen's Gambit style centre with ...d5, ...e6 and ...c5. After 7.cxd5 Nxd5 8.Nxd5 exd5 9.d4 cxd4 10.Qxd4, Black was left with an isolated queen's pawn (a pawn on d5 with no friendly pawn on the c- or e-file to defend it).

An isolated pawn is not only a weakness. It gives Black open lines on the c- and e-files and a strong square on e4, and with many pieces on the board it is often a source of attack, as in Botvinnik v Vidmar, Nottingham 1936. Here the trades on d5 and b2 had already removed four minor pieces, and fewer pieces mean less attack for the isolated pawn and more time for White to attack it. ◐ Inferred

Stockfish gives White only a small edge after the opening, about a quarter of a pawn after 14.Qxb2. The advantage is small but it is permanent: the pawn on d5 will not go away. ✓ Verified

Part 4The plans: White's first target against Black's freeing break

By move 18 both sides had doubled rooks on the d-file. White's plan has two parts: blockade the pawn on d4 with a piece that also attacks it, and trade the pieces that could defend it actively. Black's plan is to keep the pawn defended, to push it with ...d4 when that is safe, and to find activity on the c-file or the long diagonal. ◐ Inferred

The Lichess study that uses this game to teach the principle states the idea in a sentence that is worth remembering: an isolated pawn should not only be blockaded but destroyed, and a rook on d4 does both at once. A knight on d4 would blockade the pawn but would block the rooks behind it from attacking it. ^[2] ✓ Verified

Part 5The critical moments: from the blockade to the second front

Stockfish's graph of the game is flat for thirty moves, between a quarter of a pawn and most of a pawn for White, and then climbs steeply after move 32. The strategy was built in the flat part; the game was lost in the steep part.

Over the next five moves White completed the first stage. The queen went to e5, the bishop to f3 (attacking d5 a third time), and after 24.Rd4 a rook stood on the blockade square. Black defended d5 three times with the rooks and the queen and stopped every break. The pawn did not fall, but every black piece was now tied to it.

Part 6The turning point: 33...Rb8 and the choice between two weaknesses

After 31...Qe5 and 32.Rg1 White's rook joined the g-file, and Black's 32...Rf8 left the d-file to guard the king. Then 33.Qh6 put both weaknesses under attack with one move. This is the moment the principle is built for.

Black's last chance to slow the attack came at move 35. After 35.Qh8+ the king could run to the queenside with 35...Ke7, still a long way behind; Zagoriansky blocked with 35...Bg8 instead, and Stockfish's number climbed to about six pawns. White's rooks went to f4 and g5, and the queen collected the g-pawn. ✓ Verified

Part 7What Zagoriansky could have done

Black's position was passive for a long time but never lost until move 33. Stockfish's defence has one idea throughout: when the second front opens, simplify it away, and if you must give something up, give up a pawn, not the king's cover. ✓ Verified

The second line shows the defender's best tool against a two-front plan: trade the pieces that make the second front dangerous. Without queens, a weak king is not a weakness at all, and the attacker is back to a single target. ◐ Inferred

Part 8A different angle: the second front won, but not by force

The usual account of this game reads as a smooth staircase: Botvinnik fixes d5, ties Black down, opens the king, and wins. The study that teaches the game marks 29...f5 as the moment Black's position became strategically untenable. ^[2] ✓ Verified

Stockfish tells a less tidy story. White's advantage stayed around a pawn or less until move 33. The famous kingside advance actually cost White most of the edge for a moment (26.g5, where 26.h4 was better), and 29...f5, the move the study calls the point of no return, cost Black only about a quarter of a pawn. The game was decided by two later choices, 32...Rf8 and above all 33...Rb8. ✓ Verified

There is a second lesson in the numbers. A weak pawn on b6 had been in Black's position since move 21, but it became a real target only when the queen could hit it while also threatening the king. A weakness counts when it can be attacked together with another one. ◐ Inferred

Perhaps Black's long passive defence, with no counterplay at all for twenty moves, made the decisive mistake more likely: a defender who has only waited for a long time may find it hard to give up a pawn voluntarily. ? Speculative

Part 9How to use the principle of two weaknesses in your games

Most club games are not won by one big attack. They are won by an advantage that is small but lasting, a weak pawn, a bad bishop or a passive rook, turned into something bigger. The principle of two weaknesses is the most reliable way to do that.

• Before opening a second front, check that the opponent's pieces really are tied to the first weakness.
• Advance pawns so that you recapture with a pawn, not a piece, when the lines open.
• As the defender, trade queens when the second front is against your king.
• As the defender, when two weaknesses are attacked at once, give up the less important one.

Your turnPractise it

Set each position up, decide your plan before you look, then play it out against Stockfish to see whether it holds.

Part 10What to take from this game

• One weakness can be defended; two usually cannot. The pawn on d5 never fell.
• Fix and tie first, attack second. The rook on d4 blockaded d5 and tied three black pieces to it.
• The king can be the second weakness. With Black's pieces tied to d5, White's own king was safe enough for a kingside pawn advance.
• Open lines with pawns, not pieces. 26.h4 kept the edge; 26.g5 nearly gave it away.
• The defender must choose. 33...Rc8 or 33...Be8, giving up b6, kept Black in the game; 33...Rb8, saving it, lost the king.