Chess Opening Theory/1. e4/1...e5/2. Nf3/2...Nc6/3. Bc4/3...Bc5/4. b4

= Evans Gambit = The Evans Gambit is an opening out of the Giuoco Piano variation of the Italian game. The first recorded usage of the gambit is from 1824 when a Welsh sea captain with the surname of Evans played it in a tournament. This new gambit received lots of attention, leading to lots of open, tactical games and more importantly opportunities for sacrifices favoured by chess players of the era, who preferred quick, sacrificial games over long positional games.

The gambit was first analysed in 1823 and became the mainline of 1. e4 e5 for the rest of the XIX century. Many miniatures, like the Evergreen game were made out of it. What could possibly go wrong?

Before we continue its history, let’s quickly examine its 2 lines. The line preferred by romantic players is the Slow Line, castling before pushing d2-d4. There is another line that will turn out to be objectively better, the immediate d4.

However, in the latest parts of the XIX century, Wilhelm Steinitz quickly rose to becoming the best player in the world. He uncorked a new positional style of play, aiming for long term advantages instead of attacking all the time. This style of play was proven to be effective and was taken up by many players. This was a blow to the Evans gambit, because its effectiveness was dampened when Black won’t give it the tactical game it so desires. However, the real killer came in the dawn of the twentieth century. World Champion Emmanuel Lasker invented a defense to the Evans gambit named after him. His style of play was positional, inspired by Steinitz. The Lasker Defense was brutal as it let white regain the pawn, only to suck the energy out of their position by trading queens. Bad for the Gambit player.

The Evans Gambit was killed, at least the slow line. The Evans Gambit was briefly revitalised in the interwar period, when in the immediate d2-d4 line, Sevielly Tartakower came up with the Tartakower Attack, which is 7.Qb3 in the mainline for that variation. This turned out to be the best variation. Unfortunately, the Italian Game and 1.e4 itself died out in favour of the positional Queen's Gambit and the modern 1.Nf3, and with it the Evans Gambit.

The future was bleak for the gambit. However, Garry Kasparov played it against Vishwanathan Anand, increasing its popularity. That was not enough as the Evans Gambit remained to be a second-rank choice in master level.

4.b4
White offers a pawn to gain a positional advantage in the center. Should Black accept the gambit with /4...Bxb4/, White would begin launching an attack in the center with 5. c3 and later on, 6. d4.

Theory table
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1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4