What are the most popular chess openings?

Based on games played at all levels, the most popular openings are:

For White (1.e4):

1. Ruy Lopez - The most analyzed opening in chess history
2. Italian Game - Classic development, popular at all levels
3. Sicilian (Open) - When White plays 2.Nf3 and 3.d4

For White (1.d4):

1. Queen's Gambit - Solid, strategic, used by world champions
2. London System - Low theory, consistent setup
3. Catalan - Positional squeeze with fianchettoed bishop

For Black vs 1.e4:

1. Sicilian Defense - Fighting, asymmetrical positions
2. French Defense - Solid, strategic counterplay
3. Caro-Kann - Reliable, leads to stable positions

For Black vs 1.d4:

1. King's Indian Defense - Dynamic, attacking chances
2. Nimzo-Indian - Flexible, strong central control
3. Queen's Gambit Declined - Classical, solid defense

Popularity shifts over time based on fashion and theoretical developments.