The opening blunders club players make most often

WhyThisMove keeps a catalogue of 16,838 opening mistakes, each played at least 20 times. They were collected from games between players averaging 1000–1199. For this article we recounted every one of them in today's Lichess opening book (games 2013–2025), across all rating bands, and kept the real blunders: a roughly level position (evaluation between −1.50 and +1.50) where one move gives away at least two pawns.

Here are the ten played most often between players averaging 1000–1599, the move that punishes each one, and what happens to them at the top of the ladder.

How to read the figures. "Club games" are games between players averaging 1000 to 1599. The share is the number of times the mistake was played divided by the club games that reached the position. Evaluations are Stockfish's (depth 20, in pawns, from White's point of view). Percentages are cut at one decimal, never rounded up.

1. The early e4–e5 push in the Pirc: 3.e5?

After 1.e4 d6 2.d4 Nf6, pushing 3.e5? looks like it chases the knight. In fact Black takes twice: 3…dxe5 4.dxe5 Qxd1+ 5.Kxd1 Ng4, and the e5 pawn falls while White's king has lost the right to castle. Stockfish goes from +0.46 to −1.57.

• Club games: 1,186,691 times, 12.2 % of the games that reach the position.
• Games averaging 1000–1199: 16.9 %. Games averaging 2500+: 0.4 %.
• Instead: 3.Nc3, defending e4 and developing.

2. Two moves that lose to Bxf7+ in the Two Knights: 4…Nxe4? and 4…Qe7?

After 4.Ng5, White threatens f7. The answer is 4…d5, blocking the bishop. Two natural-looking moves lose material to 5.Bxf7+:

• 4…Nxe4? grabs a pawn. After 5.Bxf7+ Ke7 6.d4 h6 7.Nxe4 Kxf7, Black's king has lost castling and White is better: +0.00 → +2.24. Played 858,746 times in club games (4.7 %).
• 4…Qe7? defends f7 with the queen, but 5.Bxf7+ Kd8 wins a pawn and wrecks Black's king: +0.00 → +2.21. Played 739,598 times (4.0 %). In games averaging 2500+, 10 times out of 55,502.

3. Taking back on e5 in the Center Game: 3…fxe5??

After 1.e4 e5 2.d4 f6 3.dxe5, recapturing 3…fxe5?? is almost automatic: it is played in 92.8 % of the club games that reach the position (918,679 times). It opens the h5–e8 diagonal: 4.Qh5+ g6 5.Qxe5+ Qe7 6.Qxh8 and White is a rook up. Stockfish: +1.45 → +6.15.

The surprise is on the other side of the board: in games averaging 1000–1199, White's most common answer is 4.Nf3 (123,377 games), not the winning 4.Qh5+ (89,184 games). The mistake is made almost every time, and punished less than one time in three.

4. The bishop sacrifice that loses a piece: 3…Bxf2+?

After 1.e4 e5 2.Nf3 Bc5 3.Bc4, 3…Bxf2+? gives a bishop for a pawn: 4.Kxf2 Nf6. White's king has moved, but a whole piece is a lot more than that: +0.20 → +4.07. Played 826,034 times in club games (7.9 %); the solid move is 3…Nc6.

5. The knight that walks into a fork: 4.Nh3?

After 1.e4 e5 2.Bc4 Nc6 3.Qf3 Nf6, 4.Nh3? develops the knight to the edge and lets 4…Nd4! hit the queen and c2 at the same time. Stockfish: +0.00 → −3.21. Played 825,492 times in club games (9.8 %); 4.Ne2 develops the knight where it covers d4.

The full top ten

⚠ Thin base at 2500+: 642 games reach the position of line 4, and 700 that of line 10.

Two things stand out. Eight of the ten come from 1.e4 e5, and five of those eight turn on the f7 and f2 squares or on the e8–h5 diagonal. And the Bxf7+ sacrifice of line 3, which Stockfish calls a mistake (+0.13 → −3.70), is not so bad in practice: White scores 50.5 % after it in games averaging 1000–1199 and still 48.1 % at 2000–2199. A sacrifice that "loses" in theory can work when the defender does not know what to do next.

The catalogue in numbers

Over the 16,838 catalogued mistakes:

• leaving aside the 138 that allow or miss a forced mate, the average loss is 2.19 pawns (half of them lose 1.62 pawns or less);
• Black makes 52.7 % of them, White 47.2 %;
• 37.5 % are pawn moves, 23.9 % knight moves and 20.4 % bishop moves; 183 of them are bishop sacrifices on f7 or f2.

How to use it

Most of these mistakes are lost to one short sequence: Bxf7+ after Ng5, Qh5+ on an open diagonal, a fork on d4. Knowing the punishment is worth as much as avoiding the mistake: in our example 3, the winning reply is found less than one time in three at 1000–1199. In the app, the mistakes catalogue shows why each one fails and asks you to find the move that punishes it, and you can analyze your own games to find the ones you make.

Method

Mistakes: PostgreSQL table opening_blunders (16,838 rows, Stockfish depth 20 evaluations). The game counts stored in that table date from its creation (January 2026), so every count here was recounted in ClickHouse chess.opening_book (Lichess 2013–2025) on 1 October 2026: for each position, the games of the mistake divided by the games of every move from that position, in the bands averaging 1000–1599. Move orders are the most common route to each position. "Real blunder" = evaluation between −1.50 and +1.50 before the move and a loss of at least 2 pawns (3,891 of the 16,838 mistakes).