Ruy Lopez Main Line
White counts the number of pieces attacking d4, and the number of pieces defending it, and reckons that 8. d4 is a safe move.
8. d4? Nxd4! 9. Nxd4 exd4 10. Qxd4
Alas, Black plays 10...c5! and wherever her beautifully centralised queen moves, Black follows up with 11...c4 and the b3-bishop is trapped. (third diagram)
The moral of the story: White must prepare d4 with 8. c3.
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