Answers.Body: <p>According to <a href="https://en.m.wikipedia.org/wiki/Pure_mate" rel="nofollow noreferrer">Wikipedia</a>:</p>
  <blockquote>
  <p>&quot;A pure mate is a checkmating position in chess in which the mated king
  and all vacant squares in its field are attacked only once, and
  squares in the king's field occupied by friendly units are not also
  attacked by the mating side (unless such a unit is necessarily pinned
  to the king to avoid it interposing to block the check or capturing of
  mating unit.&quot;</p>
  </blockquote>
  <p>Essentially, a pure mate is a position in which each square around the opposing king is attacked only once by the mating side, so your first example is indeed a pure mate. However, your second example is not. While kings can be blocked off by their own units, they cannot be attacked unless they are pinned, which they aren't.</p>
  <p>To summarize, the Black king can be surrounded by its pawns and pieces so long as they are not attacked, and if they are, they must be pinned. Furthermore, the pin must prevent the pinned piece from interfering with the mate.</p>
  <p>As far as I can tell, multiple pieces may be on the board so long as the stipulations of a pure mate are met. The enemy pieces surrounding the king’s squares can be attacked, so long so as the mating piece is actually capable of mating, i.e. it cannot be captured or blocked.</p>
  <p>Wikipedia gives an example from the final position from the famous <a href="http://www.chessgames.com/perl/chessgame?gid=1018961" rel="nofollow noreferrer">Evergreen Game</a> (link to chessgames.com).</p>
  <pre><code> [Title &quot;”The Evergreen Game,” Adolf Anderssen-Jean Dufresne. Berlin GER, 1852&quot;]
  [FEN &quot;1r3kr1/pbpBBp1p/1b3P2/8/8/2P2q2/P4PPP/3R2K1 b - - 0 1&quot;]
  </code></pre>
  <p>In this position, each of the Black king's available squares that it could move to are attacked exactly once by the White pieces, and the black blocking pieces are not attacked by white pieces at all. Although the White pawn that blocks off the g7 square for the black king is attacked, this is a real pure mate from high-level play nonetheless.</p>
  <p>If you wish to see a constructed position for a pure mate, @DM has a great position in his answer to a related <a href="https://chess.stackexchange.com/questions/19207/what-is-the-most-number-of-pieces-from-one-side-that-can-be-involved-in-a-checkm">question</a> on this site.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-04-22T13:06:24.730Z
Answers.Text: This is can occur in real games, but it’s an aesthetic feature of many compositions. There are two related terms: model and ideal. They can apply to stalemates as well
Answers.UserDisplayName: Laska
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2020-09-17T12:53:37.930Z
Answers.Text: "professionnal play" is a quite anachronistic when referring to Anderssen and Dufresne...
Answers.UserDisplayName: Evargalo
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2022-12-18T05:47:20.623Z
Answers.Text: Several other definitions of the same term are covered [by Gady Costeff here](http://gadycosteff.com/cql/examples/puremate.html).
Answers.UserDisplayName: double-beep
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Answers.CreationDate: 2019-05-15T19:56:50.220Z
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Answers.LastEditDate: 2022-06-12T17:35:16.917Z
Answers.UserDisplayName: Rewan Demontay
Body: <p>Recently I heard something about <strong>pure checkmate</strong>. This is a special kind of checkmate where each of the squares around the king has to be covered by just one single piece. One simple example of this would be checkmate using two pawns and the king:</p>
  <pre><code>[FEN &quot;3k4/2PP4/3K4/8/8/8/8/8 w - - 0 1&quot;]
  </code></pre>
  <p>Unfortunately, I couldn't find any more detailed information about this topic, which is the main reason for this question.</p>
  <p>To make the question slightly more specific, I'd like to know what are the exact circumstances for a mate to be considered pure?</p>
  <p>Is it allowed to have opponent's pieces involved in the check mate? For example like this:</p>
  <pre><code>[FEN &quot;1r1q1r2/4R1p1/2p2pkp/p4Q1N/n2PP3/P5N1/5PPP/4R1K1 w - - 0 1&quot;]
  </code></pre>
  
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-09-26T11:18:36.010Z
Comments.Text: Note that the example isn't as good as it could be, because it's already not pure because g5 is attacked by white twice.
Comments.UserDisplayName: RemcoGerlich
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-09-26T15:30:00.820Z
Comments.Text: This could be fixed easily by removing the knight on f3 from the board, since he's not involved in the check mate at all. Edit: actually both (white) knights could be removed and wouldn't change that much.
Comments.UserDisplayName: Brainsucker92
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-05-15T12:00:08.473Z
Comments.Text: I heard this term in a Youtube video. But I can't remember which one. Otherwise I had added a link
Comments.UserDisplayName: Brainsucker92
Comments.ContentLicense: CC BY-SA 4.0
Comments.CreationDate: 2019-05-16T22:01:27.817Z
Comments.Text: I think it has been answered perfectly, thank you.
Comments.UserDisplayName: Brainsucker92
Tags: <checkmate><problems><terminology>
Title: What is a pure checkmate?
ThreadText: # What is a pure checkmate?
  
  (Asked by: username_0 on 2019-05-15)
  
  Recently I heard something about pure checkmate. This is a special kind of checkmate where each of the squares around the king has to be covered by just one single piece. One simple example of this would be checkmate using two pawns and the king:
  [FEN "3k4/2PP4/3K4/8/8/8/8/8 w - - 0 1"]
  
  Unfortunately, I couldn't find any more detailed information about this topic, which is the main reason for this question.
  To make the question slightly more specific, I'd like to know what are the exact circumstances for a mate to be considered pure?
  Is it allowed to have opponent's pieces involved in the check mate? For example like this:
  [FEN "1r1q1r2/4R1p1/2p2pkp/p4Q1N/n2PP3/P5N1/5PPP/4R1K1 w - - 0 1"]
  
  **Tags:** checkmate, problems, terminology
  
  > **Comments:**
  > **username_0**: I heard this term in a Youtube video. But I can't remember which one. Otherwise I had added a link  
  > **username_0**: I think it has been answered perfectly, thank you.  
  > **username_1**: Note that the example isn't as good as it could be, because it's already not pure because g5 is attacked by white twice.  
  > **username_0**: This could be fixed easily by removing the knight on f3 from the board, since he's not involved in the check mate at all. Edit: actually both (white) knights could be removed and wouldn't change that much.  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_2 on 2019-05-15. Score: 11 | Accepted answer
  
  According to Wikipedia:
  
  "A pure mate is a checkmating position in chess in which the mated king
  and all vacant squares in its field are attacked only once, and
  squares in the king's field occupied by friendly units are not also
  attacked by the mating side (unless such a unit is necessarily pinned
  to the king to avoid it interposing to block the check or capturing of
  mating unit."
  
  Essentially, a pure mate is a position in which each square around the opposing king is attacked only once by the mating side, so your first example is indeed a pure mate. However, your second example is not. While kings can be blocked off by their own units, they cannot be attacked unless they are pinned, which they aren't.
  To summarize, the Black king can be surrounded by its pawns and pieces so long as they are not attacked, and if they are, they must be pinned. Furthermore, the pin must prevent the pinned piece from interfering with the mate.
  As far as I can tell, multiple pieces may be on the board so long as the stipulations of a pure mate are met. The enemy pieces surrounding the king’s squares can be attacked, so long so as the mating piece is actually capable of mating, i.e. it cannot be captured or blocked.
  Wikipedia gives an example from the final position from the famous Evergreen Game (link to chessgames.com).
   [Title "”The Evergreen Game,” Adolf Anderssen-Jean Dufresne. Berlin GER, 1852"]
  [FEN "1r3kr1/pbpBBp1p/1b3P2/8/8/2P2q2/P4PPP/3R2K1 b - - 0 1"]
  
  In this position, each of the Black king's available squares that it could move to are attacked exactly once by the White pieces, and the black blocking pieces are not attacked by white pieces at all. Although the White pawn that blocks off the g7 square for the black king is attacked, this is a real pure mate from high-level play nonetheless.
  If you wish to see a constructed position for a pure mate, @DM has a great position in his answer to a related question on this site.
  
  > **Comments:**
  > **username_3**: This is can occur in real games, but it’s an aesthetic feature of many compositions. There are two related terms: model and ideal. They can apply to stalemates as well  
  > **username_4**: "professionnal play" is a quite anachronistic when referring to Anderssen and Dufresne...  
  > **username_5**: Several other definitions of the same term are covered [by Gady Costeff here](http://gadycosteff.com/cql/examples/puremate.html).  
  
  ---
  
  