9th note of the ancient Chinese chromatic scale (approx. A♯)
Technical term from ancient Chinese music theory, part of the 十二律 (twelve pitches). Rarely used outside historical or musicological contexts.
Isoku is the ninth pitch of the Chinese twelve-tone scale.
Archaic term for the seventh month of the lunar calendar, derived from the corresponding pitch in the ancient Chinese system. Not used in modern Japanese.
In the old lunar calendar, Isoku sometimes referred to the seventh month.