mensural notation is the basic ratio on which the notation of rhythm is built.
the basic ratio on which the notation of rhythm is built is?
mensural notation
in the 14th, 15th and 16th centuries, a period in which mensural notation was used, four basic "mensuration signs" determined the proportion between the two main units of rhythm. there were no measure or bar lines in music of this period; these signs, the ancestors of modern time signatures, indicate the ratio of duration between different note values. the relation between the "breve" and the "semibreve" was called tempus, and the relation between the "semibreve" and the "minim" was called prolatio. the breve and the semibreve use roughly the same symbols as our modern double whole note (breve) and whole note (semibreve), but they were not limited to the same proportional values as are in use today. there are complicated rules concerning how a breve is sometimes three and sometimes two semibreves. unlike modern notation, the duration ratios between these different values was not always 2:1; it could be either 2:1 or 3:1, and that is what, amongst other things, these mensuration signs indicated. a ratio of 3:1 was called "complete", perhaps a reference to the trinity, and a ratio of 2:1 was called "incomplete".
time signature
dapu (打譜) is the transcribing of old tablature into a playable form. since qin tablature does not indicate note value, tempo or rhythm, the player must work it out for him/herself. normally, qin players will learn the rhythm of a piece through a teacher or master. they sit facing one another, with the student copying the master. the tablature will only be consulted if the teacher is not sure of how to play a certain part. because of this, traditional qinpu do not indicate them (though near the end of the qing dynasty, a handful of qinpu had started to employ various rhythm indicating devices, such as dots). if one did not have a teacher, then one had to work out the rhythm by themselves. but it would be a mistake to assume that qin music is devoid of rhythm and melody. by the 20th century, there had been attempts to try to replace the "jianzi pu" notation, but so far, it has been unsuccessful; since the 20th century, qin music is generally printed with staff notation above the qin tablature. because qin tablature is so useful, logical, easy, and the fastest way (once the performer knows how to read the notation) of learning a piece, it is invaluable to the qin player and cannot totally be replaced (just as staff notation cannot be replaced for western instruments, because they developed a notation system that suited the instruments well).
guqin