Answers.Body: <p>A &quot;defense&quot; is a subset of an &quot;opening.&quot; It is a system for Black against standard opening moves such as d4 or e4. Examples are the French Defense (e6) and Sicilian Defense (c5), in response to e4, where Black actively tries to take the initiative away from White.</p>
  <p>Other &quot;openings&quot; are named from White's point of view, such as Ruy Lopez (following e4) or the Colle System (following d4). These are systems where Black more or less follows White's lead instead of making an &quot;active&quot; defense like the ones mentioned above.</p>
  
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Answers.Body: <p>The difference is whose move defined the opening.</p>
  <p>If, after 1. e4, black responds with e6, the opening is defined as a French Defense.  If, after 1. e4 e5, white plays Bc4, the opening is defined as the Bishop's Opening.  However the most common openings, such as the Queen's Gambit, aren't considered either an opening or a defense.  (Note:  The Sicilian Defense breaks this rule, but it's variations are often so well known that we refer to them as the opening name instead of a variation.  Most people call it the Najdorf, but the Morphy variation of the Ruy Lopez would be a rarity.)</p>
  
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Answers.Text: So then why is the Slav Defense a "defense" but the Queen's Gambit Declined is not? They're both based off of the same White moves, and if anything the Slav is even more common than the Queen's Gambit Declined.
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Answers.UserDisplayName: Mike Jones
Answers.Body: <p>"The opening", in general, is the first phase of a game of chess, in which both sides develop their pieces. It is followed by "the middlegame" and, if the game gets that far, "the endgame".</p>
  
  <p>When people talk about "an opening", they are referring to a particular series of opening moves that has a name. For example, 1.d4 d5 2.c4 e6 is the Queen's Gambit Declined, and 1.d4 d5 2.c4 dxc4 is the Queen's Gambit Accepted.</p>
  
  <p>Openings that are defined by the moves that Black makes are often called "defenses", since White is generally considered the attacker and Black the defender by default. For example, 1.e4 c5 is the Sicilian Defense and 1.e4 e6 is the French Defense.</p>
  
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Answers.Text: Thak you a lot!
Answers.UserDisplayName: user5691
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Answers.Text: But, interestingly, the QGA and QGD are not called "defenses" even though they're defined by Black's response. But if you respond to those same White moves with 2...c6 that's the Slav Defense.
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Answers.UserDisplayName: dfan
Body: <p>I would like to know why some openings are called "defences" and other all called "openings." What is the difference?</p>
  
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Comments.CreationDate: 2015-01-18T08:28:55.897Z
Comments.Text: Your question is about *names* of openings, I presume?
Comments.UserDisplayName: Dag Oskar Madsen
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Comments.CreationDate: 2015-01-19T13:41:37.867Z
Comments.Text: Not, is about the terms. Why sometime are called opening and others defences. Thank you.
Comments.UserDisplayName: user5691
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Comments.CreationDate: 2015-01-19T18:48:06.103Z
Comments.Text: user5691, I think that's actually what @DagOskarMadsen was getting at. I've edited the question to reflect your intent.
Comments.UserDisplayName: ETD
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Comments.CreationDate: 2021-06-11T17:04:10.887Z
Comments.Text: aThe difference is which move defined the opening name.  If, after 1. e4, black responde with e6, the opening is defined as a f
Comments.UserDisplayName: Mike Jones
Tags: <opening>
Title: What is the difference between an opening and a defence?
ThreadText: # What is the difference between an opening and a defence?
  
  (Asked by: username_0 on 2015-01-18)
  
  I would like to know why some openings are called "defences" and other all called "openings." What is the difference?
  
  **Tags:** opening
  
  > **Comments:**
  > **username_1**: Your question is about *names* of openings, I presume?  
  > **username_0**: Not, is about the terms. Why sometime are called opening and others defences. Thank you.  
  > **username_2**: username_0, I think that's actually what @DagOskarMadsen was getting at. I've edited the question to reflect your intent.  
  > **username_3**: aThe difference is which move defined the opening name.  If, after 1. e4, black responde with e6, the opening is defined as a f  
  
  ---
  
  ## 3 answers
  
  ### Answer by username_6 on 2015-01-18. Score: 7 | Accepted answer
  
  "The opening", in general, is the first phase of a game of chess, in which both sides develop their pieces. It is followed by "the middlegame" and, if the game gets that far, "the endgame".
  
  When people talk about "an opening", they are referring to a particular series of opening moves that has a name. For example, 1.d4 d5 2.c4 e6 is the Queen's Gambit Declined, and 1.d4 d5 2.c4 dxc4 is the Queen's Gambit Accepted.
  
  Openings that are defined by the moves that Black makes are often called "defenses", since White is generally considered the attacker and Black the defender by default. For example, 1.e4 c5 is the Sicilian Defense and 1.e4 e6 is the French Defense.
  
  > **Comments:**
  > **username_0**: Thak you a lot!  
  > **username_5**: But, interestingly, the QGA and QGD are not called "defenses" even though they're defined by Black's response. But if you respond to those same White moves with 2...c6 that's the Slav Defense.  
  
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  ### Answer by username_4 on 2015-02-15. Score: 2
  
  A "defense" is a subset of an "opening." It is a system for Black against standard opening moves such as d4 or e4. Examples are the French Defense (e6) and Sicilian Defense (c5), in response to e4, where Black actively tries to take the initiative away from White.
  
  Other "openings" are named from White's point of view, such as Ruy Lopez (following e4) or the Colle System (following d4). These are systems where Black more or less follows White's lead instead of making an "active" defense like the ones mentioned above.
  
  
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  ### Answer by username_3 on 2021-06-11. Score: 2
  
  The difference is whose move defined the opening.
  
  If, after 1. e4, black responds with e6, the opening is defined as a French Defense. If, after 1. e4 e5, white plays Bc4, the opening is defined as the Bishop's Opening. However the most common openings, such as the Queen's Gambit, aren't considered either an opening or a defense. (Note: The Sicilian Defense breaks this rule, but it's variations are often so well known that we refer to them as the opening name instead of a variation. Most people call it the Najdorf, but the Morphy variation of the Ruy Lopez would be a rarity.)
  
  > **Comments:**
  > **username_5**: So then why is the Slav Defense a "defense" but the Queen's Gambit Declined is not? They're both based off of the same White moves, and if anything the Slav is even more common than the Queen's Gambit Declined.  
  
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