Keys of the same name – a pair of keys of the opposite mood, the tonics of which are built on the same step. For example, O. t. C-dur and c-moll have a common main. the tone of the mode is the sound C, by the name (“name”) to which they receive names (hence the term “O. t.”). Main modal functions (T, S, and D) in O. t. are based on the same steps of the scale, which determines the special nature of their relationship. Aesthetically, O. t. with the greatest sharpness and power embody the opposite of the two main modes – major and minor. The term “O. t.” assumes identity. tone, so the concept of “O. t.” cannot be extended to keys, tonics to-rykh are built on different steps. So, contrary to the opinion of some musicologists, it is unlawful to classify single-tert tones as O. t. For example, in C-dur, the cis degree and the cis-moll tonality cannot be considered an alteration variant of the main. steps and keys, because c and sis are independent, “opposite” sounds.
References: Sposobin I. V., Elementary theory of music, M., 1951, 1958; Mazel L. A., On the expansion of the concept of the tonality of the same name, “SM”, 1957, No 2.
Yu. N. Kholopov