The scale structure of kayô-kyoku unmistakably shows us the most traditional aspect of kayô-kyoku. For example, the scale structure of the Love Phantom, which was one of the most popular rock hits in October, 1995, is pentatonic (See Transcription 1 and listen to Sound Example 3). In B minor, the scale structure of the melody is B-D-E-F#-A which can be transposed into A-C-D-E-G in A Minor. Koizumi Fumio named this scale "2-6 (ni-roku) nuki tan-onkai," or the minor scale without second and sixth scale degrees. 2-6 nuki onkai can be found in traditional Japanese music. The famous children songs called Anta gata doko sa and a folksong Sôran Bushi are examples (See Transcription 2 for Anta gata doko sa).

Example 1: 2-6 (ni-roku) nuki tan-onkai

Another popular scale structure of kayô-kyoku is "yo-na (4-7) nuki cyô-onkai," or the major scale without fourth and seventh scale degrees, which is also a pentatonic scale. Kawa no nagare no yôni, or Like the Stream of A River, sung by one of the most famous enka singers Misora Hibari, is an example (See Transcription 3 and listen to Sound Example 6). The basic scale structure consists of d, e, f#, a, and b in D major, or c, d, e, g, and a in C major, even though there are some exceptional uses of fourth and seventh.

The yo-na nuki cyo-onkai was invented by the government musicians in the Meiji Period, possibly by Isawa Syûji, to make the Western major scale fit to the Japanese tonal sense.

Isawa found that the Western major scale and Japanese Ryô scale have some common tones. In the process of making music textbooks for Japanese people, he introduced the Japanese songs in yo-na nuki onkai.

Example 2: 4-7 (yo-na) nuki cyo-onkai