data.FINGER.FRET In a guitar chord diagram, a label indicating which finger, if any, should be used to play an individual string. The index, middle, ring, and little fingers are represented by the values 1-4, while 't' is for the thumb. The values 'x' and 'o' indicate stopped and open strings, respectively.
Module MEI
Used by
<rng:data type= "positiveInteger">
<rng:param name= "minInclusive"> 1 </rng:param>
<rng:param name= "maxInclusive"> 4 </rng:param>
<rng:data type= "token">
<rng:param name= "pattern"> x|o|t </rng:param>

MEI Guidelines Version 3.0.0