E20 Nimzo-Indian Defense
E20 holds seven named lines, all under the name Nimzo-Indian Defense. It leaves A50 (Indian Defense: Normal Variation) with 2...e6 3.Nc3 Bb4. Lines of 39 other codes continue from its position, the widest spread of the 40 Nimzo-Indian Defense codes. At six plies, its reference line is the shortest of the 40 Nimzo-Indian Defense codes. With seven named lines it is the second-largest code of the 40 Nimzo-Indian Defense codes.
| # | White | Black |
|---|---|---|
| 1 | d4 | Nf6 |
| 2 | c4 | e6 |
| 3 | Nc3 | Bb4 |
The move that completes E20
The reference line of E21 plays all of these moves and continues beyond them; E20 is the position reached at 3...Bb4.
- 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.
Lines filed under E20
All seven share their first six plies, the whole reference line and then split five ways at White’s move 4.
| Name | After the shared start | Plies | At the end |
|---|---|---|---|
| Nimzo-Indian Defense | (the shared start itself) | 6 | |
| Nimzo-Indian Defense: Dilworth Gambit | 4.e4 | 7 | |
| Nimzo-Indian Defense: Kmoch Variation | 4.f3 | 7 | |
| Nimzo-Indian Defense: Mikenas Attack | 4.Qd3 | 7 | |
| Nimzo-Indian Defense: Romanishin Variation | 4.g3 | 7 | |
| Nimzo-Indian Defense: Romanishin Variation | 4.Nf3 c5 5.g3 O-O 6.Bg2 | 11 | Black castled |
| Nimzo-Indian Defense: Romanishin Variation, English Hybrid | 4.Nf3 c5 5.g3 cxd4 6.Nxd4 O-O 7.Bg2 d5 8.cxd5 Nxd5 | 16 | Black castled |
The road to E20
- 1.d4one earlier stop: A40
- 1...Nf6A45 Indian Defense
- 2.c4A50 Normal Variation
- 3...Bb4E20
The position after 3...Bb4
White has brought out the knight on c3; Black the knight on f6 and bishop on b4. White is to move and has 27 legal moves.
Codes that branch off from E20
The reference lines of seven other codes leave E20 from two of its named positions; “From” gives the last part of that position’s name.
| Code | From | Moves | Reference line |
|---|---|---|---|
| E21 | Nimzo-Indian Defense | 4.Nf3 | Nimzo-Indian Defense: Three Knights Variation |
| E22 | Nimzo-Indian Defense | 4.Qb3 | Nimzo-Indian Defense: Spielmann Variation |
| E24 | Nimzo-Indian Defense | 4.a3 | Nimzo-Indian Defense: Sämisch Variation |
| E25 | Kmoch Variation | 4...d5 5.a3 Bxc3+ 6.bxc3 c5 7.cxd5 | Nimzo-Indian Defense: Sämisch Variation |
| E30 | Nimzo-Indian Defense | 4.Bg5 | Nimzo-Indian Defense: Leningrad Variation |
| E32 | Nimzo-Indian Defense | 4.Qc2 | Nimzo-Indian Defense: Classical Variation |
| E40 | Nimzo-Indian Defense | 4.e3 | Nimzo-Indian Defense: Rubinstein System |
Closest boards in other codes
| Code | Line | Differs on |
|---|---|---|
| A17 | English Opening: Anglo-Indian Defense, Hedgehog System | four squares: d2, b4, d4, f8 |
| D35 | Queen’s Gambit Declined: Normal Defense | four squares: b4, d5, d7, f8 |
| D38 | Queen’s Gambit Declined: Ragozin Defense | four squares: g1, f3, d5, d7 |
| E11 | Bogo-Indian Defense | four squares: b1, g1, c3, f3 |
| E33 | Nimzo-Indian Defense: Classical Variation, Zurich Variation | four squares: d1, c2, c6, b8 |
| E34 | Nimzo-Indian Defense: Classical Variation, Noa Variation | four squares: d1, c2, d5, d7 |
| E38 | Nimzo-Indian Defense: Classical Variation, Berlin Variation | four squares: d1, c2, c5, c7 |
Where lines continue from here
Besides the codes above, they belong to E23, E26, E27, E28, E29, E31, E33, E34, E35, E36, E37, E38, E39, E41, E42, E43, E44, E45, E46, E47, E48, E49, E50, E51, E52, E53, E54, E55, E56, E57, E58, E59.