Preface

VII
len. Der Herausgeber dankt folgenden
Bibliotheken, die freundlich Quellenma-
terial zur Verfügung stellten: der British
Library, London; der Staatsbibliothek
zu Berlin Preußischer Kulturbesitz; der
Staats- und Universitätsbibliothek
Hamburg; dem Royal College of Music,
London, und der Stadtbibliothek Leip-
zig.
Textkritische Anmerkungen befinden
sich in den Bemerkungen am Ende die-
ser Ausgabe.
Belfast, Frühjahr 2007
Yo Tomita
Preface
At present, we cannot give a satisfactory
answer to the question as to why, almost
20 years after composing a collection of
24 Preludes and Fugues in all the keys
(the so-called Well-Tempered Clavier
dated 1722), Johann Sebastian Bach as-
sembled a Part Two in the same system-
atic fashion. However, we can learn a
great deal about the origin of this ep-
ochal work by studying the manuscripts
that have survived. From them, we learn
under what circumstances this second
collection developed, how Bach taught
his students, and how widely it was ap-
preciated by the later generations. Nu-
merous manuscripts have survived to
this day; they can all, ultimately, be
traced to two of Bach’s own manu-
scripts, which form the source traditions
“A” and “[B]”.
Source Tradition A (the London auto-
graph “A” and its dependent copies)
We have no source for the Well-Temper-
ed Clavier, Part II that is comparable to
that which we have for Part I (1722),
for which Bach’s definitive fair copy
survives. Amongst the surviving materi-
als for Part II are two autographs: an al-
most complete manuscript, the so-called
‘London autograph’ (British Library,
London, Add. MS. 35021), which con-
sists of 21 prelude-fugue pairs in un-
bound double sheets, lacking the pairs
in ck, D and f as well as the title-page;
and a single-sheet manuscript contain-
ing the Fugue in Ab (Staatsbibliothek zu
Berlin, Mus. Ms. Bach P 274). The Lon-
don autograph “A” is a mixture of fair
copies and less carefully-written scores
containing amendments of a composi-
tional nature, and it thus cannot be ex-
pected to contain the final form of each
work in every detail. About a quarter of
the material contained in it is in the
hand of Bach’s wife, Anna Magdalena.
Nevertheless it is an extremely valuable
source, as it sheds much light on how
Bach compiled and developed the col-
lection. As Yoshitake Kobayashi’s stud-
ies of paper and of Bach’s handwriting
show, Bach started working on this
project around 1739 and completed it
around 1742, between the publication
of two Clavierübungen (parts III and
IV), i.e. the so-called ‘German Organ
Mass’ (Prelude and Fugue in Eb BWV
552, Organ Chorales BWV 669–689,
Four Duets BWV 802–805) and the
‘Goldberg Variations’ BWV 988. The
most fascinating details of the work’s
origin come from a study of the process
by which it was compiled as attested to
in “A”. This shows that Bach did not
compose the work from the first prelude
in C major to the last fugue in b minor;
rather, he worked in three distinct stag-
es, as follows:
Stage 1: Bach swiftly assembled 12
prelude-fugue pairs, all in commonly-
used keys – c, d, Eb, E, e, F, fk, G, g, A,
a, and b. While some movements show
traces of being developed as Bach wrote
them out, many are fair copies. Anna
Magdalena helped her husband speed
up the process by copying nearly half of
them.
Stage 2: The pace of compilation
slowed down as it took more time for
Bach to write 10 individual pairs in Ck,
ck, D, dk, f, Fk, gk, Bb, bb, and B. Note
that most of them are in rarely-used
keys. The pairs in ck, D and f, missing in
“A”, must have existed and belonged to
this group, as the study of the complete
copies derived from it shows.
Stage 3: Before the project was com-
pleted, at least one copy, the lost model
for source “A1” (cf. Comments at the
end of this volume for sigla and full de-
scription of the sources) had been made.
It was presumably after his return from
a short trip to Berlin in summer 1741
that Bach completed the project by add-
ing two remaining pairs – in C and Ab.
Except for the prelude in Ab, which may
well have been a new composition, all
the movements were remodelled from
the 5 Preludes and 5 Fughettas (BWV
870a, 899–902) which Bach originally
assembled more than twenty years ago.
It thus appears that Bach adopted a
flexible strategy when writing the indi-
vidual pieces: this depended partly on
whether sketches and draft versions
were available, and partly on his desire
to compose new pieces for certain keys.
It should be noted that the pieces in “A”
in Bach’s hand mostly appear in his cal-
ligraphic hand, but because for him the
copying was almost always another op-
portunity for revision, Bach would re-
touch his score, often without leaving
any evidence of changes from his model.
The fact that the last completed move-
ments were written on the same paper
as the autograph of the Art of Fugue in-
dicates Bach’s shift in artistic direction
in 1742 towards a new publication
project. Despite this, Bach appears to
have continued revising the Well-Tem-
pered Clavier, Part II, when opportuni-
ties arose, as they frequently did.
In a discussion of the origin of the
work it is crucial to take into account
that Bach at the time had several out-
standing students who later became
some of the most influential figures in
the history of Western music: Gottfried
August Homilius (Cantor at the Kreuz-
schule and the Director of Music of the
three main churches in Dresden), Bach’s
student from 1735 to 1742; Johann
Friedrich Agricola (Director of the Ber-
lin Royal Kapelle), his pupil from 1738
to 1741; and Johann Philipp Kirnberger
(arguably the most influential music
critic and theorist of his generation)
from 1739 until 1741. One manuscript