Yeden, in Turkish makam theory, is the note preceding the tonic note (Durak) as the leading tone within a makam.[1]
The term Yeden has been first introduced into Turkish makam theory by Rauf Yekta Bey, he considered the Yeden a complementary feature of a makam.
The Yeden, as with the leading tone in Western classical music, leads to the resolution of a makam. While the Yeden note is generally octave equivalent with the 7th tone within the scale, sometimes it may be a different note. When it is a different note, sometimes its octave equivalent counterpart can be used in the scale, even if it is normally not in the scale.
There are three different intervals that a Yeden can have in the 53 Tone Equal Temperament in Turkish makam theory.
The Bakiye is equivalent to 4 Holdrian Commas (90.57 cents), which as a leading tone is slightly sharper than the 100 cent Western leading note.
A scale that uses this Yeden is Mahur.[2]
The Küçük Mücennep is equivalent to 5 Holdrian Commas (113.21 cents), which as a leading tone is slightly flatter than the 100 cent Western leading note.
A scale that uses this Yeden is Rast.
The Tanini is equivalent to 9 Holdrian Commas (203.77 cents), which is very slightly flatter than the 200 cent Western subtonic.
The Yeden being either Bakiye or Küçük Mücennep away from the tonic provide for a stronger resolution. If the Yeden is a Tanini away from the tonic, it's a weaker resolution.
A scale that uses this Yeden is Uşşak.