5c (dancing couple) stands facing 1c in centre of square set, numbered clw as usual.
after 5 times through, 5c finish in the middle, all other C have moved one place clw
3C Chain Progression was earlier known as Chaperoned Chain Progression
After 2nd turn the old 1c casts to 4pl on the new [1-2]
(Hint: In all ½ turns and ½Reels face dancer of own sex).
Note: Cosh explicitly tells 1c to pass Lsh in [9-24]; however the Rsh pass is quite common, and nicknamed »Mairi's Divorce«.
3c+4c cross on 2nd chord(1,2,3x,4x). This dance has top/bottom symmetry