Open Game

The Open Games are a family of chess openings beginning with the moves:

1. e4 e5

After 1.e4, when Black maintains symmetry by replying 1...e5, the result is an Open Game. The Open Games include many of the oldest and most deeply analyzed openings in chess. Play tends to continue 2.Nf3 Nc6, leading to the Ruy Lopez (3.Bb5), Italian Game (3.Bc4), Scotch Game (3.d4), and others. Black's most important alternative to 2...Nc6 is 2...Nf6, Petrov's Defense. White also has several second move alternatives like the King's Gambit (2.f4).

Other responses to 1.e4 can be classified as Semi-Open Games or Single King's Pawn Games. When written in lowercase, the term "open game" refers to a chess position where ranks, files and diagonals are open, and tending to more tactical gameplay. It is possible that an Open Game may lead to a closed game. For example, the Italian Game is an Open Game where White frequently plays d3, intending to keep the game closed, while the Sicilian Defence (1...c5), a Semi-Open Game, is frequently opened via 2.Nf3 and 3.d4 cxd4 4.Nxd4, known as the Open Sicilian.

After having been the most common response to White's most popular first move e4 until the mid-20th century, 1...e5 remains the second most popular response to 1.e4 (1...c5 is slightly more popular among tournament players). 1.e4 e5 is often among the first openings taught to new players.

Analysis

1.e4 immediately stakes a claim in the center and frees two pieces (the queen and king's bishop) for development. Bobby Fischer wrote that 1.e4 is "Best by test." On the negative side, 1.e4 places a pawn on an undefended square and weakens the squares d4 and f4. The symmetrical 1...e5 incurs the same strengths, but also the same drawbacks, for Black: White's usual response 2.Nf3 attacks the undefended pawn. Along with the Sicilian Defence (1...c5), it is the most extensively analyzed of Black's responses to 1.e4. Compared to 1...c5, the other most common response to 1.e4, 1...e5 results in more draws; in particular, there are the drawing weapons of the Berlin Defence (2.Nf3 Nc6 3.Bb5 Nf6) and Petrov's Defence (2.Nf3 Nf6). However, there are many less drawish alternative lines for both sides.

2.Nf3 Nc6

The most popular second move for White is 2.Nf3. The move attacks Black's king pawn, prepares to castle kingside, and supports playing d2–d4 in many lines. Black's usual reply to 2.Nf3 is 2...Nc6, defending the king's pawn and developing the knight. From here several named openings can arise:

3.Bb5, the Ruy Lopez (or Spanish Game), is White's most frequent move at the top level, and one of the most extensively played and analyzed openings at all levels of chess. Black's most common response is 3...a6, forcing White to make a decision between exchanging the bishop for the knight with 4.Bxc6 or retreating with 4.Ba4. Also common is 3...Nf6, the Berlin Defense. Black has several alternatives, the sharpest of which is 3...f5, the Jaenisch Gambit (or Schliemann Defense).

3.Bc4, the Italian Game, is White's second most popular move, and has been extensively analyzed for hundreds of years. It usually leads to either the Giuoco Piano (3...Bc5) or the Two Knights Defense (3...Nf6), where White may play 4.Ng5, 4.d4, or 4.d3. In the Giuoco Piano, White can play 4.c3 and 5.d4, the classical approach; 4.b4, a sharp pawn sacrifice known as the Evans Gambit; or 4.c3 and 5.d3 (also reached with other move orders), the modern approach, among various other plans.

3.d4, the Scotch Game, was popular in the 19th century and is still the third most common move. After the usual 3...exd4, White may either recapture with 4.Nxd4 with an approximately equal game, or play the Scotch Gambit (4.Bc4), a risky but dangerous tactical line against an unprepared opponent.

3.Nc3, the Three Knights Game, was also a popular move in the 19th century and is still occasionally played at the top level. Black's usual reply is 3...Nf6, leading to the Four Knights Game. It frequently leads to positional games and is generally considered less challenging for Black to defend against than the three lines above.

3.c3, the Ponziani Opening, has never achieved widespread popularity but is occasionally used as a surprise weapon.

Other third moves for White such as the Konstantinopolsky Opening (3.g3) and Inverted Hungarian Opening (3.Be2) are rarely played and offer White no advantage.

Black's second move alternatives

After 2.Nf3, there are two frequent alternatives to 2...Nc6:

2...Nf6, the Petrov Defense, a popular choice at the top level. It has a drawish reputation but there are many sharp lines. The main line is 3.Nxe5 d6 4.Nf3 Nxe4; 3.d4 is a common alternative. Alternatively, White can avoid the extensive theory of the Petrov with 3.Nc3, which often transposes into a Four Knights Game after 3...Nc6.
2...d6, the Philidor Defense, defends the pawn on e5 but has the disadvantage of restricting the mobility of Black's king's bishop, and typically leads to solid but passive positions for Black. For this reason, it largely fell out of favor by the early 20th century as Black players sought more dynamic options, but it has a dependable reputation.

The following moves are rare and generally considered dubious:

2...f5, the Latvian Gambit, a risky pawn sacrifice.
2...d5, the Elephant Gambit, another risky pawn sacrifice.
2...Qe7, the Gunderam Defense, an eccentric defense which blocks the development of the king's bishop.
2...Qf6, the Greco Defense, is weak, exposing the queen to early attack and taking up the king's knight's natural square.
2...f6, the Damiano Defense, is weak and may be met by either 3.Nxe5 or 3.Bc4 with advantage for White.
2...Bc5, the Busch–Gass Gambit, was something of an online fad in the early 2020s. It is well met by 3.Nxe5 Nc6 4.Nf3.

White's second move alternatives

White has four frequent alternatives to 2.Nf3:

2.f4, the King's Gambit, where White offers a pawn to undermine Black's center and achieve quick development. It was very popular before the 20th century with master and amateur alike.
2.Nc3, the Vienna Game, which was popular in the 19th century, also frequently features such attacks on Black's center by means of f2–f4, but there are multiple alternative plans.
2.Bc4, the Bishop's Opening, was also more popular in the past. It often transposes to the Italian Game or Vienna Game, but there are several independent lines.
2.d4, the Center Game, the least common of these four moves, where White immediately opens the center. Most often, the pawn is recovered after 2...exd4 3.Qxd4; Black may then gain a tempo on White's queen with 3...Nc6. An alternative is to sacrifice one or two pawns by offering the Danish Gambit (3.c3).

Other second moves are rare and do not gain any advantage against correct play. Some of them are:

2.Qh5, the Danvers Opening, also known as the Parham Attack or Wayward Queen Attack, is usually played only by amateurs attempting scholar's mate, though Hikaru Nakamura has experimented with it in grandmaster tournaments and was able to achieve a reasonable position.
2.Qf3, the Napoleon Opening, has even less to recommend it as Black can easily block any mating threats without compromising development.
2.Bb5, the Portuguese Opening, rarely played and well met by 2...c6 or 2...Nf6.
2.Ne2, Alapin's Opening, another offbeat try for White.
2.Ke2, the Bongcloud Attack, considered a joke opening.

Notes

Emms, John; Flear, Glenn; Greet, Andrew (2008). Dangerous Weapons: 1 e4 e5: Dazzle Your Opponents in the Open Games!. London: Everyman Chess. ISBN 9781857445428.
Hooper, David; Whyld, Kenneth (1996) [First pub. 1992]. The Oxford Companion to Chess (2nd ed.). Oxford University Press. ISBN 0-19-280049-3.
Watson, John (2006). Mastering the Chess Openings, vol 1. Gambit. ISBN 978-1-904600-60-2.

Open Game

Analysis

2.Nf3 Nc6

Black's second move alternatives

White's second move alternatives

See also

Notes

Further reading