Nimzo-Indian Defense: Three Knights Variation, Duchamp Variation, Modern Line

The Nimzo-Indian Defense: Three Knights Variation, Duchamp Variation, Modern Line is a solid and flexible chess opening that leads to rich middlegame positions.

The opening is characterized by Black's early development of the knight to f6 and the bishop to b4, putting pressure on White's center and aiming to provoke weaknesses. White's response with the Three Knights Variation involves developing the knights to f3 and c3, and the bishop to g5, creating a solid pawn structure and exerting pressure on Black's position.

The Duchamp Variation, named after the famous artist and chess player Marcel Duchamp, is a modern approach to the Nimzo-Indian Defense. It involves Black playing b6 and Bb7, fianchettoing the light-squared bishop and adding more pressure on White's central pawn on d4.

The Modern Line of this variation is defined by White's move Nd2, which aims to support the central pawn structure and prepare for a potential pawn break with e4. This move also frees the f3-knight to potentially reposition itself to better squares in the middlegame.

Both sides have various plans and ideas in this opening, leading to rich and complex middlegame positions. Black can aim for a timely pawn break with c5 or d5, while White can look for opportunities to expand in the center or launch a kingside attack.

Overall, the Nimzo-Indian Defense: Three Knights Variation, Duchamp Variation, Modern Line is a well-respected and popular opening choice for players of all levels, offering a good balance between solidity and flexibility.