- OpeningBudapest Gambit
- The mistake8.axb4
- The endCheckmate
The trap
The Budapest Gambit arises after 1.d4 Nf6 2.c4 e5. Black gives up a pawn but usually wins it back. After 3.dxe5 Ng4 the knight heads for the pawn on e5, and White defends it with 4.Bf4.
Black brings more pieces against e5: 4…Nc6 5.Nf3 Bb4+ 6.Nbd2 Qe7. The queen now stands on the e-file against the king. When White attacks the bishop with 7.a3, Black takes the pawn, 7…Ngxe5, and leaves the bishop where it is.
1. d4 Nf6 2. c4 e5 3. dxe5 Ng4 4. Bf4 Nc6 5. Nf3 Bb4+ 6. Nbd2 Qe7 7. a3 Ngxe5 8. axb4 Nd3#
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Why it's easy to fall for
The bishop on b4 is hanging, and White takes it. It looks like winning a piece, plain and simple.
But White has forgotten the queen on e7. It pins the pawn on e2 to the king, so the pawn can't capture on d3. And no other white piece covers d3: the bishop on f1 is shut in behind the pawn on e2, and the queen on d1 can't get there.
What White should have played
Leave the bishop alone for a moment. Play for example 8.Nxe5 Nxe5 9.e3. The pawn on e3 opens the diagonal for the bishop on f1, which now guards d3. Black has won back the pawn, and the position is about equal.
Note that 9.axb4?? is mate even after the knight trade: 9…Nd3#.
9. e3
White opens the way for the bishop on f1, and now d3 is covered. The position is about equal.
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How it ends
The trap ends in mate on move eight, a smothered mate: the king on e1 is surrounded by its own pieces. It costs Black nothing to set, because 7…Ngxe5 is a good move anyway.
How often does it happen?
Our numbers reach as far as 7.a3, which 166,488 of the 400,984 games between club players in that position played (42%). Black won 56% of those games. After that the position is too rare to be among the positions we have counted, so we can't say how often the mistake itself is made.
Our numbers reach as far as 7.a3, which 70,703 of the 195,599 games between strong players in that position played (36%). Black won 43% of those games. After that the position is too rare to be among the positions we have counted, so we can't say how often the mistake itself is made.
Move by move: club players
| Move | Games in the position | Played the move | Then White won | Draw | Black won |
|---|---|---|---|---|---|
| 4.Bf4 | 3,981,270 | 861,999 (22%) | 53% | 6% | 41% |
| 4…Nc6 | 861,828 | 520,979 (60%) | 52% | 6% | 41% |
| 5.Nf3 | 520,988 | 476,063 (91%) | 53% | 7% | 40% |
| 5…Bb4+ | 893,166 | 693,082 (78%) | 49% | 6% | 45% |
| 6.Nbd2 | 708,453 | 373,603 (53%) | 47% | 7% | 46% |
| 6…Qe7 | 417,978 | 396,888 (95%) | 47% | 7% | 46% |
| 7.a3 | 400,984 | 166,488 (42%) | 38% | 7% | 56% |
Move by move: strong players
| Move | Games in the position | Played the move | Then White won | Draw | Black won |
|---|---|---|---|---|---|
| 4.Bf4 | 1,568,486 | 443,910 (28%) | 54% | 7% | 39% |
| 4…Nc6 | 443,844 | 258,222 (58%) | 54% | 8% | 38% |
| 5.Nf3 | 258,216 | 249,285 (97%) | 54% | 8% | 38% |
| 5…Bb4+ | 363,506 | 278,485 (77%) | 52% | 8% | 40% |
| 6.Nbd2 | 284,500 | 173,541 (61%) | 52% | 9% | 39% |
| 6…Qe7 | 202,570 | 193,065 (95%) | 53% | 9% | 38% |
| 7.a3 | 195,599 | 70,703 (36%) | 48% | 9% | 43% |
"Played the move": of the games in the position, how many continued with the move of the trap line; then how those games ended. A position missing from the table is too rare for our numbers. Source: games on Lichess in blitz, rapid and classical, fetched 6 and 7 November 2026. Club players means games where the players average 1600 or more, strong players games where they average 2000 or more.
Explore the position on the analysis board: the moves club players choose here and how the games tend to end.
Try it
White has just taken the bishop with 8.axb4. Black to move and mate in one.
Your opponent moves…
The history
The trap is named after the German master Georg Kieninger (1902–1975). It is often said that he used it in a casual game against Godai in Vienna in 1925, but we have only found that in opening books from the 1980s, and they give no earlier source.
In 1926 a Vienna chess magazine discussed a tournament game between Godai and Kieninger with the same opening. There Kieninger played 7…Bxd2+, and it was the magazine's writer who showed 7…Ngxe5! and the mate after 8.axb4. So how the trap got Kieninger's name is not certain.
The line with 4.Bf4 is called the Rubinstein Variation. There 7.a3 is a common move, and the trap follows straight after it.
Frequently asked questions
What is the Kieninger Trap?
A trap in the Budapest Gambit. After 7.a3 Ngxe5 White takes the bishop with 8.axb4, and 8…Nd3 is mate. The pawn on e2 can't take the knight, because the queen on e7 pins it.
How does White avoid the Kieninger Trap?
By not taking the bishop until d3 is covered, for example with 8.Nxe5 Nxe5 9.e3. That opens the diagonal for the bishop on f1.
Every move on this page has been checked against the rules of chess, and every judgement of who stands better has been checked with a chess computer.
Updated November 14, 2026
7… Ngxe5
Black wins back the pawn and leaves the bishop where it is.