Kings Gambit Accepted: Rosentreter–Sørensen Gambit
King's Gambit Accepted – King's Knight Gambit, Rosentreter–Sørensen Gambit
Definition
The Rosentreter–Sørensen Gambit is a razor-sharp sub-variation of the
King’s Gambit Accepted (KGA). It arises after the moves
1. e4 e5 2. f4 exf4 3. Nf3 g5 4. h4 g4 5. Ne5!?.
White allows Black’s g-pawn to advance all the way to g4, then plants a
knight on the central outpost e5, willingly yielding a second pawn in
return for rapid development, open lines against the black king and
tactical chances on the weakened light squares.
Typical Move Order
From the starting diagram you will usually see one of two branches:
- 5…Nf6 6.d4 d6 7.Nd3 Nxe4 8.Bxf4 when White has sacrificed two pawns for rapid development.
- 5…h5 6.Bc4 Rh7 (or 6…Nh6) 7.d4 d6, keeping the extra material but giving White an enduring lead in activity.
Strategic Themes
- Central outpost e5. The white knight on e5 blocks Black’s e-pawn and interferes with castling. If exchanged, the recapture with the d-pawn opens the d-file toward d7 and f7.
- Open h-file. After 4.h4 g4, the half-open h-file can later be exploited by Rh1–h5 or Qd1–h5+ motifs.
- Lead in development vs. material. White is almost always two pawns down. Timely piece play and direct attacks are essential; if the initiative fades, the endgame is lost.
- Light-square weaknesses. The advance …g7–g5–g4 leaves f4, g5 and h6 chronically soft. Bishops on c4/b3 and queens on h5 or f7 often feature in mating combinations.
Historical Note
The gambit is named after the German analyst Hermann von Rosentreter (late 19th century) who first published its ideas, and the Danish master Jørgen Sørensen, who revived and employed it in tournaments during the 1920s–30s. Although never a mainstream GM weapon, it epitomises the romantic spirit of the King’s Gambit and periodically resurfaces in blitz and correspondence play.
Illustrative Game
Sørensen vs. Johansen, Danish Championship 1931
Black survived the attack and cashed in on material, demonstrating the double-edged nature of the line.
Practical Tips
- If you play White, pace is everything. Don’t hesitate to throw more fuel on the fire with 6.d4! or 6.Bc4! even at further material cost.
- As Black, decline speculative pawn grabs like …f4–f3!? until you are fully developed; the extra material will matter only if your king survives.
- Endgames a piece down for two pawns are usually lost for White, so avoid exchanges unless they yield a concrete tactical payoff.
Interesting Facts
- In many online databases the code ECO C37 contains no fewer than five different names for the same 5.Ne5 line, reflecting its colourful history.
- Grandmaster Luke McShane once adopted the gambit in a rapid exhibition against engines to test their defensive technique.
- The move 5.Ne5 was referred to by Steinitz as “a spark which may kindle a conflagration,” highlighting the dangerous attacking possibilities it unleashes.