Sicilian Defense: Mongoose Variation
1. e4 c5 2. Nf3 Qa5
The Sicilian Defense: Mongoose Variation is a chess opening classified as ECO B27, reached after 1. e4 c5 2. Nf3 Qa5. It is a line of the Sicilian Defense. White is to move.
In 12.6 million rated Lichess games (blitz and slower), this position was reached 338 times by this move order. White won 50%, 3% were drawn and Black won 47%. The most popular continuation is 3. Nc3 (47% of games).
Engine evaluation: +0.67 (Stockfish, depth 41; best line 3. Nc3 d6 4. d4 cxd4 5. Nxd4 Nf6)
- ECO
- B27
- Moves
- 4 plies
- FEN
rnb1kbnr/pp1ppppp/8/q1p5/4P3/5N2/PPPP1PPP/RNBQKB1R w KQkq - 2 3- PGN
1. e4 c5 2. Nf3 Qa5
Analyse with Stockfish · Board image (SVG) · Open on Lichess
Results by rating
| Average rating | Games | White / draw / Black |
|---|---|---|
| 0-1499 | 221 | |
| 1500-1999 | 89 | |
| 2000+ | 28 | |
| All | 338 |
Most played moves
| Move | Games | White / draw / Black |
|---|---|---|
| 3. Nc3 | 159 (47%) | |
| 3. Bc4 | 87 (26%) | |
| 3. c3 | 41 (12%) | |
| 3. Be2 | 13 (4%) | |
| 3. Ne5 | 8 (2%) | |
| 3. c4 | 6 (2%) | |
| 3. b3 | 5 (1%) | |
| 3. Na3 | 3 (1%) |
Master games
115 over-the-board games are classified under this line (White 57%, draw 9%, Black 34%). The strongest:
- GM Pavel V. Tregubov (2562) – GM Arman Mikaelyan (2508) 1-0 · Titled Tue 19th Mar Late · 2024-03-19
- FM Adrian Martinez Fernandez (2354) – GM Karen H. Grigoryan (2621) 0-1 · XXIX Elgoibar GM 2019 · 2019-12-16
- GM Artyom Timofeev (2567) – IM Daniel Barria Zuniga (2341) 1-0 · Titled Tue 6th Sep Late · 2022-09-06
- GM Kateryna Lagno (2547) – IM Daniel Barria Zuniga (2341) 1-0 · Titled Tue 30th Aug Early · 2022-08-30
- CM Gonzalo Alberto Navarrete Mendez (2185) – GM Samuel Sevian (2703) 0-1 · Titled Tue 28th Jun Early · 2022-06-28
Search all games of the Sicilian Defense: Mongoose Variation and its sub-variations
Highest-rated Lichess games
- IM Angelicanmade (2526) – chEss653447 (2557) 0-1 · 2026-09-01 · 180 + 0s
- tobeymaguire123 (2395) – pitrex1 (2410) 1/2-1/2 · 2026-09-04 · 180 + 0s
- mexdragon (2448) – Calzoncillo (2327) 0-1 · 2026-09-05 · 180 + 0s
Comes from
Sicilian Defense (1… c5 2. Nf3) 1. e4 c5 2. Nf3
More Sicilian Defense lines (all)
- Sicilian Defense (1. e4 c5) B20
- Sicilian Defense: Amazon Attack B20
- Sicilian Defense: Big Clamp Formation B20
- Sicilian Defense: Bowdler Attack B20
- Sicilian Defense: Brick Variation B20
- Sicilian Defense: Czerniak Attack B20
- Sicilian Defense: Czerniak Attack, Queen Fianchetto Variation B20
- Sicilian Defense: Euwe Attack, Prins Gambit B20
- Sicilian Defense: Gloria Variation B20
- Sicilian Defense: Grob Variation B20
- Sicilian Defense: Keres Variation B20
- Sicilian Defense: King David's Opening B20
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.