Classical Variation, Giuoco Pianissimo

The Giuoco Pianissimo arises when White answers the attack on e4 with 5. d3 instead of the traditional 5. d4. The pawn protects e4 and opens the c1-bishop, and White postpones the central break until it can be carried out with full support. This avoids the heavily analyzed forcing lines of the Center Attack. During the 20th century 5. d3 overtook 5. d4, and by the late part of that century it had become the main line. The position is also reached by 4. d3 Nf6 5. c3, and from the Two Knights Defense via 3...Nf6 4. d3 Bc5.

White usually castles short, brings the queen's knight to d2, places the dark-squared bishop on e3 or g5 and drops the light-squared bishop back to b3. A further retreat to c2 gives the game a Ruy Lopez flavor. On the queenside, a4 and b4 gain space and harass the c5-bishop. Black mirrors much of this with ...d6, developing the light-squared bishop to e6 or g4 and keeping the other bishop on c5 or tucking it away on b6 or a7. Black normally castles short, though a plan with ...h6 and ...g5 tends to go with queenside castling. The move ...a6 is frequent, keeping a retreat square for the bishop.

5...d6 is the most common reply, followed by 5...O-O and 5...h6. These, along with 5...a6, often transpose into one another. The Main Line runs 5...d6 6. O-O O-O 7. Re1 a6 8. Bb3 Ba7 9. h3, a slow maneuvering position. The Albin Variation, 5...d6 6. b4, gains queenside space at once, and after 6. O-O O-O 7. a4 a5 both sides fix the queenside pawns. 5...d5 is a more direct attempt to challenge the center before White is fully developed.

The line was an occasional sideline for centuries and appeared in Chigorin–Lasker at Saint Petersburg 1895–96. It had a reputation for being slow and drawish. That changed in the 1980s, when John Nunn and Anatoly Karpov took it up. Karpov played it twice against Viktor Korchnoi in the 1981 World Championship, and both games were drawn. It has remained a regular choice at the highest level. Kasparov, Kramnik, Anand, Carlsen and Nepomniachtchi have all played it, the last against Carlsen in the 2021 title match, and Anish Giri has used it to sidestep the Berlin Defense. The engine considers the position roughly level. In online play White scores somewhat better than Black, and draws are rare.