Science

...

Of course there is no way of knowing whether it was King Frederick or Baron van
Swieten who magnified the story into larger-than-life proportions. But it shows how
powerful Bach's legend had become by that time. To give an idea of how extraordinary a
six-part fugue is, in the entire Well-Tempered Clavier by Bach, containing forty-eight
Preludes and Fugues, only two have as many as five parts, and nowhere is there a six-part
fugue! One could probably liken the task of improvising a six-part fugue to the playing of
sixty simultaneous blindfold games of chess, and winning them all. To improvise an
eight-part fugue is really beyond human capability.

In the copy which Bach sent to King Frederick, on the page preceding the first sheet of
music, was the following inscription:

Regis Iussu Cantio Et Reliqua Canonica Arte Resoluta

("At the King's Command, the Song and the Remainder Resolved with Canonic Art." )
Here Bach is punning on the word "canonic", since it means not only "with canons" but
also "in the best possible way". The initials of this inscription are

R I C E R C A R

-an Italian word, meaning "to seek". And certainly there is a great deal to seek in the
Musical Offering. It consists of one three-part fugue, one six-part fugue, ten canons, and a
trio sonata. Musical scholars have concluded that the three-part fugue must be, in
essence, identical with the one which Bach improvised for King Frederick. The six-part
fugue is one of Bach's most complex creations, and its theme is, of course, the Royal
Theme. That theme, shown in Figure 3, is a very complex one, rhythmically irregular and
highly chromatic (that is, filled with tones which do not belong to the key it is in). To
write a decent fugue of even two voices based on it would not be easy for the average
musician!

Both of the fugues are inscribed "Ricercar", rather than "Fuga". This is another
meaning of the word; "ricercar" was, in fact, the original name for the musical form now
known as "fugue". By Bach's time, the word "fugue" (or fuga, in Latin and Italian) had
become standard, but the term "ricercar" had survived, and now designated an erudite
kind of fugue, perhaps too austerely intellectual for the common ear. A similar usage
survives in English today: the word "recherche" means, literally, "sought out", but carries
the same kind of implication, namely of esoteric or highbrow cleverness.
The trio sonata forms a delightful relief from the austerity of the fugues and canons,
because it is very melodious and sweet, almost dance-able. Nevertheless, it too is based
largely on the King's theme, chromatic and austere as it is. It is rather miraculous that
Bach could use such a theme to make so pleasing an interlude.

The ten canons in the Musical Offering are among the most sophisticated canons Bach
ever wrote. However, curiously enough, Bach himself never wrote them out in full. This
was deliberate. They were posed as puzzles to King Frederick. It was a familiar musical
game of the day to give a single theme, together with some more or less tricky hints, and
to let the canon based on that theme be "discovered" by someone else. In order to know
how this is possible, you must understand a few facts about canons.

...