Yamaha QX5 Owner's Manual page 25

Measure
This mark is at the end of each measure. It can be moved back and forward in time.
For 4/4 time, the first Measure mark would be as follows (the end of each measure
is the hypothetical "5th" beat).
M=0001-05-00/96
MEASURE
Moving a Measure mark a little toward the beginning (ie. slightly shortening the
length of one measure) is great for simulating a skipping record.(!)
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