Urusov Gambit

The Urusov Gambit, named after the Russian prince Sergey Semyonovich Urusov (1827–1897), arises when White meets the Berlin Defense with 3. d4 and, after 3...exd4, develops with 4. Nf3 rather than recapturing. The knight prepares e5 to hit the f6-knight, and White plans to recover the d4-pawn or play for the initiative. The position can also come from Petrov's Defense via 1. e4 e5 2. Nf3 Nf6 3. d4 exd4 4. Bc4. The engine judges it roughly balanced.

Accepting with 4...Nxe4 5. Qxd4 is the Keidansky Gambit. After 5...Nf6, White typically continues Nc3, Bg5, Qh4 and O-O-O, and answers ...O-O and ...h6 with Bxh6. Black has a sound position without obvious weaknesses, and White's compensation lies in active pieces. The retreat 5...Nd6 is an error because 6. O-O brings a crushing attack. The almost equally popular 4...Nc6 transposes to Two Knights and Scotch Gambit territory, and 4...Bc5 5. O-O Nc6 can reach the Max Lange Attack. Black can decline with the Panov Variation, 4...d5 5. exd5 Bb4+ 6. c3 Qe7+. After 7. Be2 dxc3, both 8. bxc3 and 8. Nxc3 leave the game about level.