Yovan Tsaous instrument's tuning

Dear rebetiko fans,

I am sorry for being unable to write in greek, but I would like to share this with you.

I recently had a close look to the description of Yovan Tsaous instruments in the book of Stavros Kourousis “From Tambouras to Bouzouki - The History and Evolution of the Bouzouki and its first Recordings (1926-1932)”.

After performing some calculations (hopefully without errors), I think that it was tune exactly like a Turkish TANBUR, but with some missing notes.

Here is an example for a string tuned in D
Fret 0 : RAST(D)
Fret 1 : NIM ZIRGULE
Fret 2 : ZIRGULE
(missing DIK ZIRGULE)
Fret 3 : DUGAH ?
Fret 4 : KURDI
Fret 5 : DIK KURDI
(missing SEGAH )
Fret 6 : BUSELIK
(missing DIK BUSELIK)
Fret 7 : CHARGAH (G)
Fret 8 : NIM HICAZ
Fret 9 : HICAZ
(missing DIK HICAZ)
Fret 10 : NEVA (A)
Fret 11 : NIM HISAR
Fret 12 : HISAR
(missing DIK HISAR)
Fret 13 : HUSEYNI
Fret 14 : ACEM ©
(missing DIK ACEM ASIRAN)
Fret 15 : EVITCH
(missing MAHUR)
(missing DIK MAHUR)
Fret 16 : GERDANIYE (D)

And repated to the second octave …

What do you think about it ?
That would explain why bouzouki player could not play on his instrument !

But i still do not understand why the SEGAH note is missing (perhaps because the instrument other strings were tuned in C or G, which make appear the note SEGAH ?)

Cheers
Eric
(from France)