The Spurtle is a modified form Half reel of four Across the set which interchanges the Positions of two adjacent Couples in a Longwise set and so can be used as a Progression. When danced by the first two Couples, 1st Couple should start on the Centre line, right shoulder to right shoulder, slightly above 2nd Couple's position and Facing Opposite sides:
all Dance the first two bars of a Half reel of four Across the set, 1st Man Giving right shoulder to 2nd Lady, 1st Lady Giving right shoulder to 2nd Man to start;
2nd Couple complete the Half reel of four Across, Finishing in 1st place on Opposite sides While 1st Couple Turn by the right halfway, moving Down The Set to Finish on the Centre line, right shoulder to right shoulder, slightly above 3rd Couple's position and Facing Own sides.
At the end of bar 4, 1st Couple are in exactly the same Position relative to 3rd Couple as they were to 2nd Couple at the beginning of bar 1 and so this 4-bar Figure can readily be repeated with 3rd Couple, as in bars 17-24 of the Reel, The King's Town Spurtle. When repeated again with 4th Couple, the familiar 12-bar form arises, as it appears in bars 9-20 of the Strathspey, The Blue Mess Jacket.