Hungarian Defense

The Hungarian Defense is a chess opening that begins with the moves:
The Hungarian Defense is a line in the Italian Game typically chosen as a response to the aggressive 3.Bc4. The opening is seldom seen in modern play.
The variation takes its name from a correspondence game between Paris and Pest, Hungary played from 1842–1845, but was first analyzed by Cozio in the 18th century. It has been played on occasion by some grandmasters with strong defensive-, including Reshevsky, Hort, and former world champions Petrosian and Smyslov.
With the move 3...Be7, Black avoids the complexities of the Giuoco Piano (3...Bc5), Evans Gambit (3...Bc5 4.b4), and Two Knights Defense (3...Nf6). White has an advantage in and freer , so Black must be prepared to defend a cramped position.
Main line: 4.d4.
White's best response is 4.d4, seeking advantage in the . Other moves pose fewer problems for Black: 4.c3 Nf6 (Steinitz), or 4.0-0 Nf6 5.Nc3 d6 6.d4 Bg4. After 4.d4, Black continues either 4...exd4 or 4...d6.
4...exd4.
After 4...exd4, 5.Nxd4 would transpose into a variation of the Scotch Game that gives White a spatial advantage. Weaker is 5.c3, hoping for 5...dxc3 6.Qd5, after which Black resigned in the game Midjord–Scharf, Nice Olympiad 1974 (though Black could have tried 6...Nh6 7.Bxh6 0-0 when 8.Bc1 Nb4 9.Qd1 c2 wins back the piece, so White should play 8.Bxg7 Kxg7 9.Nxc3 with advantage). However, 5...Na5, recommended by Chigorin, forces White to give up the with 6.Qxd4 or sacrifice a pawn. Also is 5...Nf6 6.e5 Ne4 (the Tartakower Variation) 7.Bd5 Nc5 8.cxd4 Ne6 (Evans).
4...d6.
Alternatively, Black generally tries to hold the center with 4...d6, when White has a choice of plans, each of which should be enough to secure a slight advantage. White can simplify to a slightly better queenless middlegame with 5.dxe5 dxe5 (5...Nxe5? 6.Nxe5 dxe5 7.Qh5! and White's on e5 and f7 wins a pawn) 6.Qxd8+ (6.Bd5 is also possible) Bxd8 7.Nc3 Nf6. Or White can close the center with 5.d5 Nb8, followed by Bd3 and expansion on the with c4, resulting in positions resembling those from the Old Indian Defense. Finally, with 5.Nc3 White can retain in the center and obtain active piece play.
Harding and Botterill, in their 1977 book on the Italian Game, conclude that, "The Hungarian Defence can only be played for a draw. White should have an edge in most lines."
References.
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