Starting from 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 d6 5.Bxc6+ bxc6 6.d4, players enter the Ruy Lopez: Morphy Defense, Modern Steinitz Defense (5.Bxc6+ 5...bxc6) — ECO C73. With 27,992 games on record, the patterns below come from the largest practical sample available.
History and Notable Players
It arises from the Ruy Lopez: Morphy Defense, Steinitz Deferred. Among the most prolific White practitioners are Hans Joachim Hecht (12 games), Aleksandar Matanovic (10 games), George Alan Thomas (10 games). Black-side regulars include Heikki MJ Westerinen (18 games), Bogdan Sliwa (17 games), Valeri Yandemirov (15 games).
Move Diversity and Theory Depth
What players actually play after the opening moves depends heavily on rating. At 1200 Elo, the top reply is exd4, played 36.9% of the time. There are 5 other moves seeing meaningful share, and 72.2% of games stick to established theory. Entropy: 2.71. By 2500, exd4 dominates at 51.9% of replies; only 2 viable alternatives remain and 99.1% of moves are theory. Entropy drops to 1.28. That entropy collapse is the signature of a line where preparation pays off: at the top, players know the best move and play it.
Common Mistakes
- Drifting away from main theory — At 400 Elo, theory adherence sits at 61.2% — versus 96.3% at 2000. The most popular deviation is Nf6 (played 16.7% of the time at 400, much less so up top). It looks fine but quietly hands the better-prepared side an edge.
- Neglecting development — It can feel productive to make extra pawn moves early, but falling behind in piece development is what loses most amateur games — especially in open positions where active pieces find squares fast.
- Playing without a plan — Each Ruy Lopez: Morphy Defense, Modern Steinitz Defense (5.Bxc6+ 5...bxc6) middlegame demands a specific approach. Decide whether the position calls for attack, manoeuvre, or simplification before reaching for a move.
Practice on Chessiverse
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