Black controls the d4-square in the center and maintains symmetry. 1.e4 e5 gives rise to many of the oldest and most deeply analyzed openings in the game. Play most commonly continues 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. Other Open Games include the King's Gambit (2.f4) and Vienna Game (2.Nc3).
After having been the most common pair of opening moves until the 20th century, 1...e5 remains the second most popular response to White's first move 1.e4 (1...c5 is slightly more popular among tournament players).[1] Other responses to 1.e4 are termed 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.[2]
White opens by playing 1.e4, which is the most popular opening move and has several strengths – it immediately stakes a claim in the center, and frees two pieces (the queen and king's bishop) for action. The oldest openings in chess follow 1.e4. Bobby Fischer wrote that 1.e4 is "Best by test."[3] On the negative side, 1.e4 places a pawn on an undefended square and weakens the squares d4 and f4. If Black keeps the symmetry by replying 1...e5, the result is an Open Game.[2][4]
The most popular second move for White is 2.Nf3 (the King's Knight Opening), attacking Black's king pawn, preparing to castlekingside, and preparing for d2–d4 in many lines. Black's usual reply to 2.Nf3 is 2...Nc6, defending the king's pawn without restricting the movement of the king's bishop. From here several named openings can arise.
The Ruy Lopez or Spanish Game (3.Bb5) is one of the most popular openings at all levels of chess, and one of the most extensively analyzed. 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. A common alternative is the Berlin Defense (3...Nf6), which can continue into a heavily analyzed drawish line after 4.0-0 Nxe4, the Open Berlin. Black has several alternatives, the sharpest of which is the Schliemann Defense (3...f5).
The Italian Game (3.Bc4) is White's second most popular move, usually leading to either the Giuoco Piano (3...Bc5) or the Two Knights Defense (3...Nf6). The name "Italian Game" is also used as a synonym for the Giuoco Piano by many writers.
The Scotch Game (3.d4) 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.
The Four Knights Game (3.Nc3 Nf6) was also quite popular in the 19th century. It frequently leads to positional games and is generally considered less challenging for Black to defend against than the three lines above. Less commonly, 3....g6 or 3...Bb4 (the Three Knights Game) are possible.
Black's most important alternative to 2...Nc6 is 2...Nf6, known as Petrov's Defense or Russian Defense. It is a common opening in high level play, where it has a reputation as a drawing weapon. White can avoid the extensive theory of the Petrov by playing 3.Nc3, which could transpose into a Four Knights Game after 3...Nc6. Another possibility is 3... Bb4.
The Philidor Defense (2...d6) 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 and is still occasionally seen at grandmaster level.
The Elephant Gambit (2...d5) and the Latvian Gambit (2...f5) are considered very risky for Black. The Gunderam Defense (2...Qe7) is an offbeat choice which blocks the development of the king's bishop and has never achieved widespread popularity. The Damiano Defense (2...f6) may be met by either 3.Nxe5 or 3.Bc4 with advantage and is almost never seen. The Busch–Gass Gambit (2...Bc5), which was something of an online fad in the early 2020s, is well met by 3.Nxe5 Nc6 4.Nf3.
The most popular alternatives to 2.Nf3 are 2.f4 (the King's Gambit), 2.Nc3 (the Vienna Game), and 2.Bc4 (the Bishop's Opening). The King's Gambit was popular before the 20th century with master and amateur alike. White offers a pawn to undermine Black's center and achieve quick development. The Vienna Game also frequently features such attacks on the Black center by means of f2–f4. Some of its lines, as well some in the Bishop's Opening, can transpose to variations of the King's Gambit.
In the Center Game (2.d4), White immediately opens the center, though if the pawn is to be recovered after 2...exd4 with 3.Qxd4, Black may 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).
The early development of the queen in the Danvers Opening (2.Qh5, also known as the Parham Attack) is usually played only by amateurs, though Hikaru Nakamura has experimented with it in grandmaster tournaments and was able to achieve a reasonable position.[7][8] The Napoleon Opening (2.Qf3) has even less to recommend it as Black can easily block any mating threats without compromising their development. The Portuguese Opening (2.Bb5) and Alapin's Opening (2.Ne2) are offbeat tries for White, but neither gain any advantage against correct play. The Bongcloud Attack (2.Ke2) is considered a joke opening.
Bologan, Victor (October 2014). Bologan's black weapons in the open games : how to play for a win If white avoids the Ruy Lopez. Alkmaar, The Netherlands. ISBN9789056915438. OCLC878505291.{{cite book}}: CS1 maint: location missing publisher (link)
Davies, Nigel, 1960- (2005). Play 1e4 e5! : a complete repertoire for Black in the open game. London: Everyman Chess. ISBN1857444019. OCLC71338396.{{cite book}}: CS1 maint: multiple names: authors list (link) CS1 maint: numeric names: authors list (link)
Emms, John. (2000). Play the open games as Black : what to do when White avoids the Ruy Lopez. London: Gambit. ISBN1901983277. OCLC45466779.
Lokander, Martin (7 January 2016). Opening repertoire : the open games with black. London. ISBN9781781941942. OCLC922562228.{{cite book}}: CS1 maint: location missing publisher (link)
