La **defendo de la du ĉevaloj** estas unu el la Malfermoj de la reĝa peono en ŝako.

4. Ĉg5
------

Diag.1 **Karakterizaj unuaj movoj**

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
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|  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | a | b | c | d | e | f | g | h |  |
| 8 | a8 | b8 | c8 | d8 | e8 | f8 | g8 | h8 | 8 |
| 7 | a7 | b7 | c7 | d7 | e7 | f7 | g7 | h7 | 7 |
| 6 | a6 | b6 | c6 | d6 | e6 | f6 | g6 | h6 | 6 |
| 5 | a5 | b5 | c5 | d5 | e5 | f5 | g5 | h5 | 5 |
| 4 | a4 | b4 | c4 | d4 | e4 | f4 | g4 | h4 | 4 |
| 3 | a3 | b3 | c3 | d3 | e3 | f3 | g3 | h3 | 3 |
| 2 | a2 | b2 | c2 | d2 | e2 | f2 | g2 | h2 | 2 |
| 1 | a1 | b1 | c1 | d1 | e1 | f1 | g1 | h1 | 1 |
|  | a | b | c | d | e | f | g | h |  |

 |
| **1. e4 e5**
**2. Ĉf3 Ĉc6**
3**. Kc4 Ĉf6** |

Diag.2 **sekvo 4.Ĉg5**

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 

|  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | a | b | c | d | e | f | g | h |  |
| 8 | a8 | b8 | c8 | d8 | e8 | f8 | g8 | h8 | 8 |
| 7 | a7 | b7 | c7 | d7 | e7 | f7 | g7 | h7 | 7 |
| 6 | a6 | b6 | c6 | d6 | e6 | f6 | g6 | h6 | 6 |
| 5 | a5 | b5 | c5 | d5 | e5 | f5 | g5 | h5 | 5 |
| 4 | a4 | b4 | c4 | d4 | e4 | f4 | g4 | h4 | 4 |
| 3 | a3 | b3 | c3 | d3 | e3 | f3 | g3 | h3 | 3 |
| 2 | a2 | b2 | c2 | d2 | e2 | f2 | g2 | h2 | 2 |
| 1 | a1 | b1 | c1 | d1 | e1 | f1 | g1 | h1 | 1 |
|  | a | b | c | d | e | f | g | h |  |

 |
| **4. Ĉg5 d5**
**5. exd5 Ĉxd5** |

Diag.3 **Var. Bogoliubow**

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 

|  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  | a | b | c | d | e | f | g | h |  |
| 8 | a8 | b8 | c8 | d8 | e8 | f8 | g8 | h8 | 8 |
| 7 | a7 | b7 | c7 | d7 | e7 | f7 | g7 | h7 | 7 |
| 6 | a6 | b6 | c6 | d6 | e6 | f6 | g6 | h6 | 6 |
| 5 | a5 | b5 | c5 | d5 | e5 | f5 | g5 | h5 | 5 |
| 4 | a4 | b4 | c4 | d4 | e4 | f4 | g4 | h4 | 4 |
| 3 | a3 | b3 | c3 | d3 | e3 | f3 | g3 | h3 | 3 |
| 2 | a2 | b2 | c2 | d2 | e2 | f2 | g2 | h2 | 2 |
| 1 | a1 | b1 | c1 | d1 | e1 | f1 | g1 | h1 | 1 |
|  | a | b | c | d | e | f | g | h |  |

 |
| **6. Kb5+ c6**
**7. dxc6 bxc6**
**8. Df3** |

Post karakterizaj unuaj movoj **1.e4 e5 2.Ĉf3 Ĉc6 3.Kc4 Ĉf6**, la Blankoj povas elekti inter du ĉefaj linioj : **4. Ĉg5** aŭ
**4. d3**

Tio estas iom riska, ĉar ĝi ebligas efikajn reagojn de la Nigroj.

Fakte post Ĉg5, la Nigroj daŭrigas:

* 'jen per **4.... Kc5;** En tiu varianto, la Blankoj ne akceptu la forkan atakon en f7, ĉar ili tiam havos gravajn problemojn. La Nigroj donacas sian kurieron en f2, kaj profitas fortan atakon danke al Ce4+.
* 'jen per *varianto Traxler*:  **4.... d5;** En tiu pozicio, la Blankoj ludu **exd5**, al kio la Nigroj povas respondi jen **Ĉxd5**, jen **Ĉa5**

### 5. ... Ĉd5

La Blankoj povas daŭrigi

* jen per d4 kaj poste aroki (gambito de l' peono d4 por malfermi la kolumnon "e");
* jen per la **Fegatello-atako** : Ĉxf7 kiu daŭrigas per Kxf7 Df3+ kaj Ke6

La ĉefa varianto okazas tiel : **1. e4 e5; 2. Ĉf3 Ĉc6; 3. Kc4 Ĉf6; 4. Ĉg5 d5; 5. exd5 Ĉa5. *(Diag. 2)*** 

Sekvas **6. Kb5+ c6; 7. dxc6 bxc6 8. Df3 = varianto Bogoliubow *(Diag. 3)***, al kiu la Nigroj devas pluiri per Rb8 kaj la Blankoj ne devas preni la peonon c6, (kio faciligus la ludon por la Nigroj). Bona movo por la Blankoj estas Ke2.

4. d3
-----

d3 estas multe pli trankvila ol Ĉxg5 kaj pli sekura. La Blankoj daŭrigos per sistemo kiu entenas Ĉbd2, c3, b4, Re1,Ĉf1,Ĉg3 kaj h3 por eviti najlado de la ĉevalo per eventuala alveno de la nigra kuriero g4. Post d3, la Nigroj povas aliri al Itala malfermo, en kiu okazos proksimume la saman strategion.

Ĉefa linio
----------

**1.e4 e5**
**2.Ĉf3 Ĉc6**
**3.Kc4 Ĉf6**

La plej kutimaj variaĵoj estas
------------------------------

**4.d3**
**4.d4** exd4
... **5.e5** d5 6.Kb5 Ĉe4 7.Ĉxd4 Kc5 8.Ĉxc6 Kxf2+ 9.Rf1 Dh4
... **5.Ĉg5**
... **5.0-0** Ĉxe4 **6.Te1** d5
... 7.Kxd5 Dxd5 8.Ĉc3 Da5 9.Ĉxe4 Ke6 10.Kg5 h6 11.Kh4 g5 12.Ĉf6+ Re7 13.b4 Atako Yurdansky
... **7.Ĉc3** Variaĵo Canal
**4.Ĉg5 Kc5**
**4.Ĉg5 d5**
... 5.exd5 b5
... 5.exd5 **Ĉd4**
... 5.exd5 Ĉd4 **6.c3** b5 7.Kf1 Ĉxd5 8.Ĉe4
... 5.exd5 Ĉxd5 **6.d4** Atako Lolli
... 5.exd5 Ĉxd5 6.d4 **Kb4+**

Atako Max Lange
---------------

### Ĉefa linio

1.e4 e5
2.Ĉf3 Ĉc6
3.Kc4 Ĉf6
4.d4 exd4
5.0-0 **Kc5**
La plej bonaj respondoj estas:

**6.e5** d5 7.exf6 dxc4 8.Te1+ Ke6
... 9.Ĉg5 Dd5 10.Ĉc3 Df5
... 11.g4 Dg6 12.Ĉce4 Kb6 13.f4 0-0-0
... **11.Ĉce4** Kf8
... 9.Ĉg5 **g6**
... **9.fxg7**
6.e5 **Ĉg4**
6.e5 Ĉg4 **7.c3**

Atako Fegatello
---------------

### Ĉefa linio

**1.e4 e5**
**2.Ĉf3 Ĉc6**
**3.Kc4 Ĉf6**
**4.Ĉg5**
La plej bona respondo estas:

4.Ĉg5 **d5** 5.exd5 Ĉa5
... 6.Kb5+
... 6.Kb5+ **c6** 7.dxc6 bxc6
... 8.Df3 **Dc7** 9.Kd3
... 8.Df3 **Tb8**
... 8.Ke2 h6 **9.Ĉh3**

Ankaŭ eblas
-----------

4.Ĉg5 d5
... 5.exd5 **Ĉxd5** 6.Ĉxf7
... 5.exd5 **Ĉa5**
... 5.exd5 Ĉa5 **6.d3**
... 5.exd5 Ĉa5 6.d3 **h6** 7.Ĉf3 e4 8.De2 Ĉxc4
... 9.dxc4 Kc5 10.Ĉfd2
... 9.dxc4 **Ke7**

Vidu ankaŭ
----------

* Listo de ŝakaj malfermoj
* Malfermita malfermo
* Fermita malfermo
* Duonfermita malfermo
* Duonmalfermita malfermo
* Neregula malfermo
* Flanka malfermo