Modern Defense and Pterodactyl Variations: Anhanguera
Modern Defense
Definition
The Modern Defense is a hyper-modern chess opening in which Black allows White to occupy the center with pawns and pieces, planning to undermine it later with pawn breaks and fianchettoed bishops. It most often begins 1.e4 g6 or 1.d4 g6, followed by …Bg7 and …d6. The ECO codes most commonly associated with the Modern Defense are B06–B07.
Typical Move Order
After 1.e4:
- e4 g6
- d4 Bg7
- Nc3 d6 (3…c6 and 3…a6 are also common)
Strategic Ideas
- Black delays classical pawn occupation of the center and places pieces to attack the white centre pawns later with …c5, …e5 or …f5.
- The fianchettoed bishop on g7 exerts long-range pressure on the light squares (d4, e5, b2).
- Because development is flexible, the Modern can transpose into the Pirc, King’s Indian Defence, or certain lines of the Sicilian, making it attractive to players who like a varied repertoire.
Historical Notes
The Modern Defense rose to prominence in the mid-20th century with the influence of players such as Richard Réti, Bent Larsen, and later Viktor Korchnoi and Tiger Hillarp Persson. Its hyper-modern philosophy—controlling rather than occupying the center—was initially controversial but is now mainstream.
Illustrative Example
Fischer – Pachman, Palma de Mallorca 1970 (abridged):
Fischer calmly built a broad pawn center and eventually opened lines on the queenside, illustrating White’s typical plan of expanding before Black’s counterplay arrives.
Interesting Facts
- Because it can start with 1…g6 against almost any first move, the Modern is favored by club players who want a “one-size-fits-all” response.
- The opening is sometimes called the “Robatsch Defense” after Austrian grandmaster Karl Robatsch, one of its early specialists.
Standard Pterodactyl
Definition
The Standard Pterodactyl is a sharp variation of the Modern Defense in which Black combines a kingside fianchetto with the immediate break …c5 and a subsequent queen sortie to a5 or b6. The unusual piece placement—especially the queen on the a-file and the bishop on g7—evokes a “wing-flapping” image, hence the whimsical name “Pterodactyl.”
Characteristic Move Order
- e4 g6
- d4 Bg7
- Nc3 c5 (The key Pterodactyl thrust)
- dxc5 Qa5 or 4…Bxc3+ 5.bxc3 Qa5
Strategic Themes
- Early queen excursion to the a-file attacks the c5-pawn, pin-pressures the c3-knight, and eyes e1–e5 squares.
- Black relies on dynamic piece activity and tactical motifs rather than classical pawn structure.
- The line often transposes to asymmetrical Sicilian structures once …c5 is recaptured.
Historical & Theoretical Significance
Although never a mainstream grandmaster choice, the Standard Pterodactyl has been explored in correspondence and engine play, revealing many forcing sub-lines that can punish an unprepared opponent. Modern theoreticians such as FM Léonid Krgović have published niche monographs devoted solely to the Pterodactyl.
Miniature Example
Kazhgaleyev – Stefanova, Internet Blitz 2021:
Black’s adventurous queen eventually gets trapped, demonstrating the razor-sharp nature of the Standard Pterodactyl.
Trivia
- The name was coined on Usenet in the 1990s; the imagined “flapping” of the queen and bishop reminded posters of a flying reptile.
- It remains popular in blitz and bullet because of its surprise value and forcing tactics.
Sicilian Variation (of the Pterodactyl)
Definition
The Sicilian Pterodactyl Variation is the branch of the Pterodactyl reached via a Sicilian move order rather than the pure Modern. Black begins with 1…c5, but after 2.Nf3 pivots to …g6 and …Bg7, exploiting flexible transposition possibilities.
Standard Move Order
- e4 c5
- Nf3 g6
- d4 cxd4
- Nxd4 Bg7
- Nc3 Nc6 (5…Qa5 signals a jump to the Anhanguera Variation—see below)
How It Is Used
- Players who normally answer 1.e4 with the Sicilian can sidestep heavy theoretical main lines (such as the Open Sicilian Najdorf or Dragon) while still keeping a Sicilian pawn on c5.
- The resulting positions blend ideas from the Accelerated Dragon, the Modern Defense, and the Pirc, giving Black numerous transpositional tricks.
Notable Game
Moradiabadi – Kryakvin, Aeroflot Open 2016:
White seized space with e5–e6, showing one of the most common strategic tests Black must pass in the Sicilian Pterodactyl.
Interesting Facts
- Many databases classify this line under ECO B27 or B50 rather than the Modern codes, so its true popularity is under-reported.
- Engine analysis reveals near equality for Black, but practical win-rates skew toward the second player because of the unusual structures.
Anhanguera Variation
Definition
The Anhanguera Variation is the most ambitious sub-line of the Pterodactyl in which Black supplements the …c5 advance with an instant queen leap to a5. It is named after “Anhanguera,” a Cretaceous Brazilian pterosaur larger and more aggressive than the archetypal Pterodactyl.
Canonical Move Sequence
- e4 c5
- Nf3 g6
- d4 cxd4
- Nxd4 Bg7
- Nc3 Qa5 (The defining Anhanguera move)
Strategic & Tactical Motifs
- The queen on a5 simultaneously pins the knight on c3 and pressures e1, discouraging an early c2–c4 break.
- Black often follows with …Nc6 and …Nf6, building rapid piece-play while White untangles the pin.
- Because Black’s queen is exposed, a mistimed …Qa5 can be met by Bd2, Nb3, or Nd5, forcing retreat or concessions.
Historical Background
The name appeared in Brazilian chess literature around 2005, popularized by IM Herman Claudius van Riemsdijk. The variation has since featured in Brazilian Championships and numerous Lichess Titled Arenas.
Model Game
B. Jobava – M. Rodshtein, European Club Cup 2019:
Rodshtein steered into a dynamic middlegame with opposite-side castling, illustrating Black’s aggressive intentions.
Anecdotes & Trivia
- An “Anhanguera Gambit” sub-line sacrifices the d-pawn with 6…Nf6 7.f3 d5!?, claiming rapid development as compensation.
- Brazilian GM Alexandr Fier once used the Anhanguera to upset a 2700-rated opponent in online bullet, sparking a surge of Twitch interest in 2020.