One can arbitrarily designate any pitch as Sa (the tonic) and build the series from there. While all thaats contain seven notes, many ragas (of the "audav" and "shadav" type) contain fewer than seven and some use more. A raga need not to use every tone in a given thaat; the assignment is made according to whatever notes the raga does contain (but see note 5). The relatively small number of thaats reflects Bhatkhande's compromise between accuracy and efficiency: the degree of fit between a raga and its thaat is balanced with the desire to keep the number of basic thaats small. Ambiguities inevitably arise. For example, Raga Hindol, assigned to Kalyan thaat, uses the notes S G M D N, which are also found in Marwa thaat. Jaijaiwanti contains both shuddha Ni and komal Ni (and sometimes both versions of Ga as well), which by definition corresponds to no thaat. Bhatkande resolved such cases "by an ad hoc consideration, appealing to musical performance practice" (see Ramesh Gangolli's article, cited in note 4 above).