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In music, a fugue ( ) is a contrapuntal compositional technique in two or more voices, built on a subject (theme) that is introduced at the beginning in imitation (repetition at different pitches) and recurs frequently in the course of the composition. The English term ''fugue'' originated in the 16th century and is derived from the French word ''fugue'' or the Italian ''fuga''. This in turn comes from Latin, also ''fuga'', which is itself related to both ''fugere'' ("to flee") and ''fugare'' ("to chase").〔"Fugue, ''n''." ''The Concise Oxford English Dictionary'', eleventh edition, revised, ed. Catherine Soanes and Angus Stevenson (Oxford and New York: Oxford University Press, 2006). (【引用サイトリンク】title=Oxford Reference Online, subscription access )〕 The adjectival form is ''fugal''.〔"Fugal, ''adj''." ''The Concise Oxford English Dictionary'', eleventh edition, revised, ed. Catherine Soanes and Angus Stevenson (Oxford and New York: Oxford University Press, 2006). (【引用サイトリンク】title=Oxford Reference Online, subscription access )〕 Variants include ''fughetta'' (literally, "a small fugue") and ''fugato'' (a passage in fugal style within another work that is not a fugue).〔 A fugue usually has three sections: an exposition, a development, and finally, a recapitulation that contains the return of the subject in the fugue's tonic key, though not all fugues have a recapitulation. In the Middle Ages, the term was widely used to denote any works in canonic style; by the Renaissance, it had come to denote specifically imitative works.〔"Fugue (fugue; Ger. Fuge; Lat., It., Sp., fuga )." ''The Harvard Dictionary of Music'' (Cambridge: Harvard University Press, 2003), (【引用サイトリンク】title=credo Reference )〕 Since the 17th century,〔 for discussion of the changing use of the term throughout Western music history.〕 the term ''fugue'' has described what is commonly regarded as the most fully developed procedure of imitative counterpoint. Most fugues open with a short main theme, the subject, which then sounds successively in each voice (after the first voice is finished stating the subject, a second voice repeats the subject at a different pitch, and other voices repeat in the same way); when each voice has entered, the ''exposition'' is complete. This is often followed by a connecting passage, or ''episode'', developed from previously heard material; further "entries" of the subject then are heard in related keys. Episodes (if applicable) and entries are usually alternated until the "final entry" of the subject, by which point the music has returned to the opening key, or tonic, which is often followed by closing material, the coda.〔"Fugue", ''The Concise Oxford Dictionary of Music'', fourth edition, ed. Michael Kennedy (Oxford and New York: Oxford University Press, 1996). ISBN 0-19-280037-X (【引用サイトリンク】title=Oxford Reference Online, subscription access )〕 In this sense, a fugue is a style of composition, rather than a fixed structure. The form evolved during the 18th century from several earlier types of contrapuntal compositions, such as imitative ricercars, capriccios, canzonas, and fantasias. The famous fugue composer Johann Sebastian Bach (1685–1750) shaped his own works after those of Johann Jakob Froberger (1616–1667), Johann Pachelbel (1653–1706), Girolamo Frescobaldi (1583–1643), Dieterich Buxtehude (c. 1637–1707) and others.〔 With the decline of sophisticated styles at the end of the baroque period, the fugue's central role waned, eventually giving way as sonata form and the symphony orchestra rose to a dominant position. Nevertheless, composers continued to write and study fugues for various purposes; they appear in the works of Wolfgang Amadeus Mozart (1756–1791)〔 and Ludwig van Beethoven (1770–1827),〔 as well as modern composers like Dmitri Shostakovich (1906–1975). ==Musical outline== A fugue begins with the ''exposition'' and is written according to certain predefined rules; in later portions the composer has more freedom, though a logical key structure is usually followed. Further entries of the subject will occur throughout the fugue, repeating the accompanying material at the same time. The various entries may or may not be separated by ''episodes''. What follows is a chart displaying a fairly typical fugal outline, and an explanation of the processes involved in creating this structure. S = subject; A = answer; CS = countersubject ===The exposition=== A fugue begins with the exposition of its subject in one of the voices alone in the tonic key.〔 G. M. Tucker and Andrew V. Jones, "Fugue", in ''The Oxford Companion to Music'', ed. Alison Latham (Oxford and New York: Oxford University Press, 2002). ISBN 0-19-866212-2 (【引用サイトリンク】title=Oxford Reference Online, subscription access )〕 After the statement of the subject, a second voice enters and states the subject with the subject transposed to another (often closely related) key, which is known as the ''answer''. To make the music run smoothly, it may also have to be altered slightly. When the answer is an exact copy of the subject to the dominant, it is classified as a ''real answer''; if it has to be altered in any way it is a ''tonal answer''.〔 A tonal answer is usually called for when the subject begins with a prominent dominant note, or where there is a prominent dominant note very close to the beginning of the subject.〔 To prevent an undermining of the music's sense of key, this note is transposed up a fourth to the tonic rather than up a fifth to the supertonic. Answers in the subdominant are also employed for the same reason. While the answer is being stated, the voice in which the subject was previously heard continues with new material. If this new material is reused in later statements of the subject, it is called a ''countersubject''; if this accompanying material is only heard once, it is simply referred to as ''free counterpoint''. The countersubject is written in invertible counterpoint at the octave or fifteenth. The distinction is made between the use of free counterpoint and regular countersubjects accompanying the fugue subject/answer, because in order for a countersubject to be heard accompanying the subject in more than one instance, it must be capable of sounding correctly above or below the subject, and must be conceived, therefore, in invertible or double counterpoint.〔〔"Invertible Counterpoint" ''The Oxford Companion to Music'', ed. Alison Latham (Oxford and New York: Oxford University Press, 2002) (【引用サイトリンク】title=Oxford Reference Online, subscription access )〕 In tonal music invertible contrapuntal lines must be written according to certain rules because several intervallic combinations, while acceptable in one particular orientation, are no longer permissible when inverted. For example, when the note "G" sounds in one voice above the note "C" in lower voice, the interval of a fifth is formed, which is considered consonant and entirely acceptable. When this interval is inverted ("C" in the upper voice above "G" in the lower), it forms a fourth, considered a dissonance in tonal contrapuntal practice, and requires special treatment, or preparation and resolution, if it is to be used. The countersubject, if sounding at the same time as the answer, is transposed to the pitch of the answer. Each voice then responds with its own subject or answer, and further countersubjects or free counterpoint may be heard. When a tonal answer is used, it is customary for the exposition to alternate subjects (S) with answers (A), however, in some fugues this order is occasionally varied: e.g., see the SAAS arrangement of ''Fugue No. 1 in C Major, BWV 846'', from the ''Well-Tempered Clavier, Book 1'' by J. S. Bach. A brief codetta is often heard connecting the various statements of the subject and answer. This allows the music to run smoothly. The codetta, just as the other parts of the exposition, can be used throughout the rest of the fugue. The first answer must occur as soon after the initial statement of the subject as possible; therefore the first codetta is often extremely short, or not needed. In the above example this is the case: the subject finishes on the quarter note (or crotchet) B-flat of the third beat of the second bar which harmonizes the opening G of the answer. The later codettas may be considerably longer, and often serve to (a) develop the material heard so far in the subject/answer and countersubject and possibly introduce ideas heard in the second countersubject or free counterpoint that follows (b) delay, and therefore heighten the impact of the reentry of the subject in another voice as well as modulating back to the tonic.〔Paul Walker, "Fugue, §1: A Classic Fugue Analysed" (【引用サイトリンク】title=Grove Music Online )〕 The exposition usually concludes when all voices have given a statement of the subject or answer. In some fugues, the exposition will end with a redundant entry, or an extra presentation of the theme.〔 Furthermore, in some fugues the entry of one of the voices may be reserved until later, for example in the pedals of an organ fugue (see J. S. Bach's Fugue in C major for Organ, BWV 547). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「fugue」の詳細全文を読む スポンサード リンク
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