When playing around with his just discovered "13-tone scale" in the early 1970s, Heinz Bohlen produced some peculiar (Paul Erlich would say "idiosyncratic") ideas about notation of BP. An example can be seen below:

Thus starts one version of a number of transcriptions that Bohlen made around Christmas 1973 of an old Christmas carol. Here he put it into s-delta, which required three flats since the reference scale he used at that time was k-gamma (later i-gamma). The pitch was defined by the letter K sitting on the third line as a clef. Other clefs in use were R and L.

Meanwhile the gamma scale has fallen from favor and has been replaced by the lambda scale, and Manuel Op de Coul's suggestion to use c, d, e etc. as note names makes the whole BP notation question a lot easier. Now the traditional clefs can be used, just labeled "BP" as in the example shown here:

BP notation as proposed by Manuel Op de Coul

The lambda scale is the reference here; therefore c-lambda carries neither sharps nor flats.

In analogy to the Circle of Fifths of the traditional Western scale, BP also possesses a key circle. The septimal major third 9/7 (the BP third) assumes the role of the fifths in this case, closing the circle in 13 steps (or rather completing one loop of the spiral). With BP lambda as a reference scale the circle looks like this:

Accordingly each lambda scale key is recognizable by its proprietary number of sharps or flats:

Like the minor scales in the traditional system, there are other modes in BP that share the key signatures with the lambda scale. The signature allocations are shown in the following three tables. Which one of the other modes will assume the role of an alternative to lambda can only be decided by practical application, and this decision may take a long time to be made.

Placement of sharps
Number of sharps		1	2	3	4	5	6
Lambda		E	G	J	B	D	F sharp
Harmonic		J	B	D	F sharp	H sharp	A sharp
Dur I		B	D	F sharp	H sharp	A sharp	C sharp
Moll I (Delta)		C	E	G	J	B	D
Moll II (Pierce)		G	J	B	D	F sharp	H sharp

Placement of flats
Number of flats		1	2	3	4	5	6
Lambda		A	H	F	D flat	B flat	J flat
Harmonic		E	C	A	H	F	D flat
Dur I		G	E	C	A	H	F
Moll I (Delta)		H	F	D flat	B flat	J flat	G flat
Moll II (Pierce)		C	A	H	F	D flat	B flat

For reasons of practicality, the tranSpectra collective proposes an entirely different system, based on 3 staffs, using the Greek letters α to ν as note names and avoiding key signatures and accidentals. Quotation: "As noted previously, methods of notation of Bohlen-Pierce music are still evolving, but the following system is suggested for notating Bohlen-Pierce scores and individual instrumental or vocal parts in concert pitch. For simplicity, normal five line staves are used, with one leger line between adjacent staves; each (chromatic) scale step is represented by moving up or down one line or space (with no accidentals). The anticipated total instrumental range requires three staves, with clef symbols (S = soprano, A = alto, B = bass) chosen to prevent confusion with conventional staff notation."

Accidental-free notation, proposed by the tranSpectra collective
Picture courtesy of tranSpectra