The rag was a modification of the march made popular by John Philip Sousa, with additional polyrhythms coming from African music.[5] It was usually written in 2/4 or 4/4 time with a predominant left hand pattern of bass notes on odd-numbered beats and chords on even-numbered beats accompanying a syncopated melody in the right hand. According to some sources the name "ragtime" may come from the "ragged or syncopated rhythm" of the right hand.[2] A rag written in 3/4 time is a "ragtime waltz."
Ragtime is not a "time" (meter) in the same sense that march time is 2/4 meter and waltz time is 3/4 meter; it is rather a musical genre that uses an effect that can be applied to any meter. The defining characteristic of ragtime music is a specific type of syncopation in which melodic accents occur between metrical beats. This results in a melody that seems to be avoiding some metrical beats of the accompaniment by emphasizing notes that either anticipate or follow the beat ("a rhythmic base of metric affirmation, and a melody of metric denial"[21]). The ultimate (and intended) effect on the listener is actually to accentuate the beat, thereby inducing the listener to move to the music. Scott Joplin, the composer/pianist known as the "King of Ragtime", called the effect "weird and intoxicating." He also used the term "swing" in describing how to play ragtime music: "Play slowly until you catch the swing...".[22] The name swing later came to be applied to an early genre of jazz that developed from ragtime. Converting a non-ragtime piece of music into ragtime by changing the time values of melody notes is known as "ragging" the piece. Original ragtime pieces usually contain several distinct themes, four being the most common number. These themes were typically 16 bars, each theme divided into periods of four four-bar phrases and arranged in patterns of repeats and reprises. Typical patterns were AABBACCC′, AABBACCDD and AABBCCA, with the first two strains in the tonic key and the following strains in the subdominant. Sometimes rags would include introductions of four bars or bridges, between themes, of anywhere between four and 24 bars.[2
from wikipedia which I realise can be edited, but this sounded pretty good.
