First-move advantage
New In Chess observed in its 2000 Yearbook that of the 731,740 games in its database, White scored 54.8% overall; with the two most popular opening moves, White scored 54.1% in 349,855 games beginning 1.e4, and 56.1% in 296,200 games beginning 1.d4. The main reason that 1.e4 was less effective than 1.d4 was the Sicilian defence (1.e4 c5), which gave White only a 52.3% score in 145,996 games.