Breaking Down The Final Chess Match In The Netflix Miniseries ‘The Queen’s Gambit’
By: Kurry Tran
Tags: Alphazero, Netflix Originals, Chess, The Queens Gambit, Netflix

The Queen’s Gambit

An opening is a named, initial sequence of moves by both players. A gambit is an opening where a player attempts to sacrifice a piece in the hopes of gaining a future advantage. The Queen’s Gambit is one of many possible openings, described in the dialogue of the show:

Elizabeth Harmon plays pawn to Queen four. Borgov plays pawn to Queen four. Harmon plays pawn to Queen Bishop four. The Queen’s Gambit.

Queen’s Gambit

Queen’s Gambit is one of the top three openings used by AlphaZero. The bars show the win percentage when playing the opening with the left when playing White and the right when playing Black. The line graph shows the preference of the opening based on the amount of training time for the algorithm.

Early on in the show, Mr. Shaibel—a custodian at the orphanage where Elizabeth Harmon, the series’ heroine, grows up, who becomes her first chess teacher — stresses to Harmon that she needs to learn the Sicilian Defense, which leads her, in the early episodes, to open King four (e4) when White.

The Sicilian is really best thought of as a large collection of systems and variations, all of which begin with 1.e4 c5. ― Garry Kasparov

But — per the novel on which the show was based — prior to the final match against Russian world champion Vasily Borgov, Harmon tells her friend and fellow chess prodigy Benny that she wants to avoid Borgov’s Sicilian — and that, if she were to draw White, she would play the Queen’s Gambit to do so. In the final match with Borgov, this is the first time that Harmon opens with Queen four (d4), while in every other match, she opened with King four (e4).

Harmon Opened To King four (e4) Against Harry In Kentucky

Harmon Opened To King four (e4) Against Benny In Las Vegas

Harmon Opened To King four (e4) Against Borgov In Paris

Harmon Opened To Queen four (d4) Against Borgov In Moscow

Borgov Takes Non-Standard Line

Borgov declines, moves pawn to King four. The Albin Counter-Gambit. Borgov’s second move is a bit of a surprise. Normally, Borgov would do something more solid, but here, he’s going against his own style and playing a rare line to win.

After Harmon (White) makes the Queen’s Gambit, the opening will subsequently fall into one of two categories, depending on Borgov’s (Black) response: accepted or declined.

If Black takes the pawn at Queen Bishop four (c4), the response is defined as accepted, since Black allows White to sacrifice the pawn.

Queen’s Gambit Accepted

If Black does not take the pawn at Queen bishop four (c4), the response is defined as declined, since Black does not take White’s sacrifice. In the case of a decline, the standard (Orthodox Line) move for Black is to move a pawn to King three (e6), providing defense for the pawn at Queen four (d5). The Albin Counter-Gambit is an uncommon defense of the Queen’s Gambit in which Black moves a pawn to King four (e5).

Queen’s Gambit Declined (Orthodox Line)

Queen’s Gambit Declined (Albin Counter-Gambit / Borgov’s Line)

Harmon’s response was a complete deviation from the Albin, which must’ve surprised him right back, whilst allowing her to get out into the open.

In the scene, after a few moves occur off-camera, we see that Borgov’s pawn at King four (e5) is still on the board, meaning Harmon has declined to take the Albin Counter-Gambit —the main line would be to play your knight to Queen Bishop three, but she first plays her pawn to King four, allowing space for her bishop, then plays Knight to Queen Bishop three. Such a divergence from the main line is called a “deviation”.

Modern Chess Openings by R.C. Griffith (1939)

Reenactment Of Scene

Harmon Declines The Albin Counter-Gambit

Who was winning when the game was adjourned?

To determine this, I input the board position — that is, which pieces are still on the board, with the coordinates of each piece — into the Stockfish chess engine, which output a score of the match. The position is written and stored using the Forsyth-Edwards Notation (FEN) to record the state of the board.

The Queen’s Gambit FEN: rnbqkbnr/ppp1pppp/8/3p4/2PP4/8/PP2PPPP/RNBQKBNR b KQkq c3 0 2

You can copy and paste the string above into any chess diagram creator that accepts FEN; all standard notations are determinant, meaning they will produce the same output across all compatible programs.

The chess engine score is a single value: either a signed number indicating which player has the advantage on the board, or a signed alphanumeric combination indicating how many moves it will take the winning player to force a checkmate. A positive (“+”) sign indicates the score is with respect to White, and a negative (“-”) means the score is with respect to Black.

To calculate the score, the chess engine considers a number (depth) of possible moves both players can take in the future based on the board’s current position. As a signed number, the score indicates how many points ahead a player is; the unit of measure is the pawn. A score of +2.25 or -2.25 indicates that White or Black, respectively, leads by 2.25 pawns. A score of +M3 means that White can force a checkmate in three moves, and vice versa.

There is a strong correlation between the chess engine’s score and the proportion of victory for each player. MIT Media Lab took the chess engine score of 120,000+ positions and the proportion of victory for each position from an archive of 750,000 games, finding a best-fit line to approximate the relationship to win percentage. Given a chess engine score, you simply multiply the value by 100 to match the units — appropriately named centipawns — of the graph below, then you can find the probability of a win for either side using the best-fit line.