Alekhine Defense: O'Sullivan Gambit
1. e4 Nf6 2. e5 Nd5 3. d4 b5
The Alekhine Defense: O'Sullivan Gambit is a chess opening classified as ECO B03, reached after 1. e4 Nf6 2. e5 Nd5 3. d4 b5. It is a line of the Alekhine Defense. White is to move.
In 12.6 million rated Lichess games (blitz and slower), this position was reached 852 times by this move order. White won 42%, 4% were drawn and Black won 54%. The most popular continuation is 4. Bxb5 (53% of games).
Engine evaluation: +1.40 (Stockfish, depth 40; best line 4. Bxb5 c5 5. c4 cxd4 6. Nf3 e6)
- ECO
- B03
- Moves
- 6 plies
- FEN
rnbqkb1r/p1pppppp/8/1p1nP3/3P4/8/PPP2PPP/RNBQKBNR w KQkq - 0 4- PGN
1. e4 Nf6 2. e5 Nd5 3. d4 b5
Analyse with Stockfish · Board image (SVG) · Open on Lichess
Results by rating
| Average rating | Games | White / draw / Black |
|---|---|---|
| 0-1499 | 181 | |
| 1500-1999 | 508 | |
| 2000+ | 163 | |
| All | 852 |
Most played moves
| Move | Games | White / draw / Black |
|---|---|---|
| 4. Bxb5 | 452 (53%) | |
| 4. Nf3 | 203 (24%) | |
| 4. c4 | 75 (9%) | |
| 4. f4 | 52 (6%) | |
| 4. c3 | 25 (3%) | |
| 4. Qf3 | 12 (1%) | |
| 4. Nc3 | 7 (1%) | |
| 4. b3 | 6 (1%) |
Master games
52 over-the-board games are classified under this line (White 60%, draw 5%, Black 35%). The strongest:
- GM Alexandra Kosteniuk (2513) – FM Nadya Toncheva (2228) 0-1 · Titled Tue 24th May Late · 2022-05-24
- IM Balazs Csonka (2498) – FM Nadya Toncheva (2228) 1-0 · Titled Tue 31st May Early · 2022-05-31
- IM Milosz Szpar (2490) – CM Jude Shearsby (2224) 0-1 · Titled Tue 8th Jul Early · 2025-07-08
- GM Artem Chernobay (2484) – FM Nadya Toncheva (2207) 1-0 · Titled Tue 29th Mar Late · 2022-03-29
- GM Maksim Chigaev (2632) – CM Ivan Kochiev (2046) 1-0 · Titled Tue 14th Feb Early · 2023-02-14
Search all games of the Alekhine Defense: O'Sullivan Gambit and its sub-variations
Highest-rated Lichess games
- PawnsTractorist (2573) – VonSinnen (2573) 1-0 · 2026-09-06 · 180 + 0s
- TregubenkoKolya_2010 (2601) – FM AlexVerzhansky (2436) 1-0 · 2026-09-05 · 180 + 0s
- Schach_Huenstetten (2475) – VonSinnen (2551) 1-0 · 2026-09-07 · 180 + 0s
Comes from
Alekhine Defense (2… Nd5 3. d4) 1. e4 Nf6 2. e5 Nd5 3. d4
More Alekhine Defense lines (all)
- Alekhine Defense (1. e4 Nf6) B02
- Alekhine Defense: Brooklyn Variation B02
- Alekhine Defense: Brooklyn Variation, Everglades Variation B02
- Alekhine Defense: Buckley Attack B02
- Alekhine Defense: Hunt Variation, Lasker Simul Gambit B02
- Alekhine Defense: Hunt Variation, Matsukevich Gambit B02
- Alekhine Defense: Hunt Variation, Mikenas Gambit B02
- Alekhine Defense: Kmoch Variation B02
- Alekhine Defense: Krejcik Variation B02
- Alekhine Defense: Krejcik Variation, Krejcik Gambit B02
- Alekhine Defense: Maróczy Variation B02
- Alekhine Defense: Mokele Mbembe B02
Opening names and moves from the Lichess openings dataset; statistics from the Lichess open database, 2026-09 (CC0), sample of 12.6 million games, bots excluded; evaluations from Lichess cloud analysis (all CC0). Master games from The Week in Chess #920–#1664 by Mark Crowther, used with permission.