The Kopec System is named after the AmericanInternational MasterDanny Kopec. It was never played at the top level because it was thought that Black would instantly gain an advantage, because White's bishop blocks the d-pawn.
Basics
With 2.Bd3!?, White seemingly blocks his d-pawn, violating the principle that "one should not block one's central pawns with pieces"; however, the bishop is not meant to stay on d3. On the third move, White will play Nf3, and on the fourth move, c3, vacating a square for the bishop, and then Bc2 on the fifth move. On move six, White will likely play d4. Much of the game's play revolves around White aiming for the perfect center, by playing a timely d2–d4 advance. White also usually plays h3 in order to prevent Black from trading his light-squared bishop with White's crucial knight at f3, which should support the critical d4 advance. In the event that this knight is traded, White will play d3 and maneuver more pieces to support the d4 advance eventually. White's light-squared bishop is known as the "Kopec bishop". From seemingly passive play, it often springs to life from three diagonals, frequently switching between them. Those diagonals are the b1–h7 diagonal, the a2–g8 diagonal, and the a4–e8 diagonal. White's usually maneuvers Nd2–f1–g3. Alternatively, it could be maneuvered Nd2–f1–e3, preventing a pin against the knight on f3, and threatening to jump into d5. Kopec said that the Kopec System was useful for taking Sicilian players into Ruy Lopez type positions, where they would be less comfortable. Kopec also said that the Kopec was like the King's Indian Attack, but that the light-squared bishop is more useful on c2 than g2.
Variations
Black has a variety of ideas to try against the Kopec System. He can turn the game into a "Russian", "Dragon" or "French" position. After either 2...d6, 2...Nc6, or 2...e6, White will play 3.Nf3. Black has several choices in terms of pawn structure. He can enter a "Dragon" structure, where Black plays...d6 and...g6. He can enter the "Russian" structure, where he plays...d6,...g6, and...e5, placing a clamp on d4, at the cost of a hole on d5. Black can enter the "Lopez" structure, where he plays...e5 at some point, without finachettoing his, and placing a clamp on d4, at the cost of a hole on d5. In the "French" structure, Black plays...e6 to support...d5. In all cases, the plan is the same: On the third move, White plays Nf3; on the fourth, c3; and on the fifth, Bc2. Regardless of structure, White will develop his pieces and aim for a on d4, supported by the pawn on c3.
