E21 Nimzo-Indian Defense: Three Knights Variation
E21 holds four named lines, all under the name Nimzo-Indian Defense. It leaves E20 (Nimzo-Indian Defense) with 4.Nf3. None of its four lines contains a capture. That final move, by the knight, opens a line for the rook on h1.
| # | White | Black |
|---|---|---|
| 1 | d4 | Nf6 |
| 2 | c4 | e6 |
| 3 | Nc3 | Bb4 |
| 4 | Nf3 |
Lines filed under E21
All four share the start 1.d4 Nf6 2.c4 e6 and then split two ways at White’s move 3.
| Name | After the shared start | Plies |
|---|---|---|
| Nimzo-Indian Defense: Three Knights Variation | 3.Nc3 Bb4 4.Nf3 | 7 |
| Nimzo-Indian Defense: Three Knights Variation, Korchnoi Variation | 3.Nc3 Bb4 4.Nf3 c5 5.d5 | 9 |
| Nimzo-Indian Defense: Three Knights Variation, Euwe Variation | 3.Nc3 Bb4 4.Nf3 c5 5.d5 Ne4 | 10 |
| Nimzo-Indian Defense: Three Knights Variation, Shocron Gambit | 3.Nf3 Bb4+ 4.Nc3 c5 5.d5 b5 | 10 |
Nimzo-Indian Defense: Three Knights Variation, Korchnoi Variation
- 3.Nc3 The knight leaves b1 for c3, opening a line for the rook on a1.
- 3...Bb4 The bishop leaves f8 for b4, opening a line for the rook on h8, attacking the knight on c3, pinning the knight on c3 to its king.
- 4.Nf3 The knight leaves g1 for f3, opening a line for the rook on h1.
- 4...c5 The c-pawn advances two squares to c5, covering b4 and d4, opening a line for the queen on d8.
- 5.d5 The d-pawn advances to d5, covering c6 and e6, opening a line for the queen on d1.
Nimzo-Indian Defense: Three Knights Variation, Euwe Variation
- 3.Nc3 The knight leaves b1 for c3, opening a line for the rook on a1.
- 3...Bb4 The bishop leaves f8 for b4, opening a line for the rook on h8, attacking the knight on c3, pinning the knight on c3 to its king.
- 4.Nf3 The knight leaves g1 for f3, opening a line for the rook on h1.
- 4...c5 The c-pawn advances two squares to c5, covering b4 and d4, opening a line for the queen on d8.
- 5.d5 The d-pawn advances to d5, covering c6 and e6, opening a line for the queen on d1.
Nimzo-Indian Defense: Three Knights Variation, Shocron Gambit
- 3.Nf3 The knight leaves g1 for f3, opening a line for the rook on h1.
- 3...Bb4+ The bishop leaves f8 for b4, opening a line for the rook on h8, giving check.
- 4.Nc3 The knight leaves b1 for c3, opening a line for the rook on a1.
- 4...c5 The c-pawn advances two squares to c5, covering b4 and d4, opening a line for the queen on d8.
- 5.d5 The d-pawn advances to d5, covering c6 and e6, opening a line for the queen on d1.
The road to E21
- 1.d4 … 1...Nf6two earlier stops: A40, A45
- 2.c4A50 Normal Variation
- 3...Bb4E20 Nimzo-Indian Defense
- 4.Nf3E21
The position after 4.Nf3
White has brought out the knight on c3 and knight on f3; Black the knight on f6 and bishop on b4. Black could capture with Bxc3+. Black is to move and has 33 legal moves.
Closest boards in other codes
| Code | Line | Differs on |
|---|---|---|
| D38 | Queen’s Gambit Declined: Ragozin Defense | two squares: d5, d7 |
| E11 | Bogo-Indian Defense | two squares: b1, c3 |
| D37 | Queen’s Gambit Declined: Three Knights Variation | four squares: b4, d5, d7, f8 |
| D39 | Queen’s Gambit Declined: Ragozin Defense, Vienna Variation | four squares: c1, c4, g5, d7 |
| E10 | Indian Defense: Anti-Nimzo-Indian | four squares: b1, c3, b4, f8 |
| E22 | Nimzo-Indian Defense: Spielmann Variation | four squares: d1, g1, b3, f3 |
| E24 | Nimzo-Indian Defense: Sämisch Variation | four squares: g1, a2, a3, f3 |
Where lines continue from here
Five named lines filed under other codes pass through the position after 4.Nf3. They belong to E20, E43.