Micrologus

...Guido is said to have invented a method of notation in which three or four equal-spaced horizontal lines are drawn and notes are written on and between the lines to indicate pitch (the principle of the method of indicating pitch is the same as that of today's five-line staff), and to have used this method to notate Gregorian chant. He is also said to have been the one who introduced the six-note scale method of ut, re, mi, fa, sol, and la, making it easier to sight-sing music. His well-known theoretical work is Micrologus (little logic), which also describes new counterpoint in the era when polyphonic music was moving from parallel organum to free organum. [Toguchi Kosaku]...

*Some of the terminology that mentions "micrologus" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…グィードは，等間隔で水平に3～4本の直線を引き，その線上と線間に音符を書き入れて音高を表示する記譜法(音高の表示法では，今日の5線譜と原理は同じ)を考案し，この記譜法でグレゴリオ聖歌を記譜し，また，ウトut，レre，ミmi，ファfa，ソルsol，ラlaの6音の階名唱法を始めて楽譜の視唱を容易にした人と言い伝えられている。彼の残した理論書としては《ミクロログスmicrologus(小論理)》などが知られており，この著作には，多声音楽が平行オルガヌムから自由オルガヌムに移行する時代の新しい対位法についても記されている。【戸口 幸策】。…

※「micrologus」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報