411 REFERENCE · Wikibooks
Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Nxe5/3...Nxe5/4. d4
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Irish gambit Irish gambit
4. d4
White takes over the centre with tempo on Black's knight.
Black's knight has two places to go, 4...Ng6 or 4...Nc6, where after 5. d5 Ne5 6. f4, the knight ends up on g6 after all.