1. d4 d5 2. e4 dxe4 3. Nc3 Nf6 4. f3 exf3 5. Qxf3 Qxd4 6. Be3 Qb4 7. O-O-O 7… Bg4?? 8. Nb5 Bxf3 9. Nxc7#
Classic opening traps · Blackmar-Diemer Gambit
Halosar Trap
Black pins the queen with Bg4. The knight jumps to b5 threatening mate on c7; if Black takes the queen, it is mate.
In September 2026 this trap position came up in 348 games; 42% of the players with Black fell for it.
348games reached the trap
42%Black falls for it
86%White punishes it
77%White wins afterwards
By rating
| Lichess rating | Reached | Fell | Punished |
|---|---|---|---|
| Under 1200 | 27 | – | – |
| 1200–1599 | 142 | 41% | 81% |
| 1600–1999 | 162 | 41% | 91% |
| 2000 and up | 17 | – | – |