The Modern Scotch
The Scotch Game is the most “open” of all the Open Games. In fact this is the only really Open Game, in its essence, which matches the traditional terminology.
The move 3.d2-d4 breaks immediately the symmetry. White tries to occupy the centre and gain additional space. Rapid contact between the opposing forces takes place, in fact much quicker than in the other open (and not only open...) games, which increases the value of every move and requires from both sides tremendous accuracy at a very early stage of the game. Positions with opposite castles arise much more often in the Scotch than in all the other Open Games put together.
Alexander Khalifman is a GM and FIDE Senior Trainer, FIDE World Chess Champion in 1999. He won the Soviet Union Youth Championship (1982, 1984), the European Under-20 Championship (1985), the Russian Championship (1996). He was a member of the gold medal-winning Russian team at the Chess Olympiads in 1992, 2000 and 2002, and at the 1997 World Team Chess Championship. Author of many books as Opening for White According to Anand, Opening for White According to Kramnik.
Sergei Soloviov is an IM, author of many books as Boris Spassky's 400 Selected Games, Leko's One Hundred Wins.