Chess opening
The Nadanian Variation (sometimes called the Nadanian Attack) of the Grünfeld Defence is a chess opening characterised by the moves:
1. 
2. 
3. 
4. 
5. 
The Nadanian Variation is classified in the "Encyclopaedia of Chess Openings" with the code D85.
 ;templatestyles src="Template:TOC_left/styles.css" / ;
History.
The variation is named after the Armenian International Master Ashot Nadanian, who first employed it in 1996. His analysis was published in the 67th volume of Chess Informant.
The birth of the variation has caused major ripples in the chess world. One of the world's most authoritative chess editions "New in Chess Yearbook" printed on the front cover of the 45th volume the following: "A Revolution in the Gruenfeld: 5.Na4!?!". Grandmaster Jonathan Rowson wrote in his book "Understanding the Grünfeld" that Nadanian "should be congratulated for seeing what everyone has seen, and thinking what nobody had thought".
The famous chess theoretician Grandmaster Igor Zaitsev wrote in the Russian chess magazine "64":The continuation 5.Na4 of Armenian chess player Nadanian shakes by the extraordinariness. Yes, extraordinariness, because it is unusual among the unusual. A voluntary removal of the knight from the centre, yet that has gone on advantage? Therefore, the value of such centrifugal maneuver is beyond a simple theoretical novelty, in a certain measure it is a challenge to chess foundations, an attempt to grope new properties in two-dimensional chess space.
Theory.
White's fifth move is overprotecting the key c5-square in the Grünfeld Defence, thus aspires to prevent an attack on the pawn centre by c7–c5. The extravagancy of White's idea is that they break at once two opening principles: avoid moving the same piece twice, and avoid placing a knight on the edge of the board. However, according to Nadanian, the position after the fifth move is an exception to the rules. By placing the knight on а4, White takes under control the critical square c5, and by next move 6.e4 will return a tempo back, as Black too will play an already developed piece (knight on d5).
White should aspire to the following arrangement: e4, Be3, Be2, Nf3, 0-0, Rc1, Nc5. Black in turn should not allow this scheme for what it is necessary for them to put pressure on the d4 pawn.
The main line continues 5...Bg7 6.e4 Nb6 (Avrukh's 6...Nb4 is also interesting) 7.Be3 0-0 8.Nf3 Bg4 (instead 8...Nxa4 9.Qxa4 c5 10.Rd1 Qb6 11.Rd2 was good for White in Korchnoi–Sutovsky, Dresden 1998) 9.Be2 Nc6 10.d5 Ne5 11.Nxe5 Bxe2 12.Qxe2 Nxa4 with approximately equal chances.
Another possible line is 5...e5 6.dxe5 Nc6 (suggested by Igor Zaitsev and first played by Mikhalchishin), which is according to Lubomir Kavalek "perhaps the only way to punish the white knight's venture to the edge of the board". After 7.a3 (Nadanian's idea) 7...Bf5 8.Nf3 Qd7 9.e3 0-0-0 10.Be2 (Eingorn gives 10.Bb5 Qe6) 10...Qe7 11.Qb3 Bg7 according to Yelena Dembo Black has a powerful initiative (Kantsler–Avrukh, Israel 1999).
Use.
The variation's most devoted practitioner has been its eponym, Ashot Nadanian. Various famous players such as Viktor Korchnoi, Maxime Vachier-Lagrave, Bu Xiangzhi, Alexander Riazantsev, Igor Lysyj, Walter Browne, Smbat Lputian, Timur Gareyev, Jonathan Rowson, Andrei Kharlov, Bogdan Lalić have employed it at some time or another, though few have made it their main line against the Grünfeld Defence.
Modified versions.
There are also modified versions of Nadanian's idea.
References.
 ;templatestyles src="Reflist/styles.css" / ;