It always sounded to me like the clap in Leadbelly's interpretation of Black Betty ( <a href="https://www.youtube.com/watch?v=Fii6PX0-VXs" rel="nofollow">https://www.youtube.com/watch?v=Fii6PX0-VXs</a> ) is syncopated because you raise the hammer on the beat ("Ohhh"?) and start the downswing on the beat ("Bam"?) but it lands (<i>clap</i>) according to gravity, not the beat.<p>(some tunes that were popular on both sides of the iron curtain made sense, like the "Chicken Dance", but then one may find others, like "16 Tons", interpreted here with the original* lyrics by an army band: <a href="https://www.youtube.com/watch?v=LVMANcPkDAg" rel="nofollow">https://www.youtube.com/watch?v=LVMANcPkDAg</a> )<p>* Did they have this song via Paul Robeson? Some commie quickly came up with a parody: "We're flying to bomb the Union"