Fred Astaire and The Long Under-sleeve
A customer of mine,( duck carving customer) Russell, from The LL, asked me about this old sleeve manipulation. If you watch old movies from the 1920s and 30 you will often see sleeves that the undersleeve back seems to fit not quite right. It gathers at the back. Well, they fit beautifully. This gathering of cloth gives forward ease and movement. It acts as a pleat. Or a gusset ( see bottom photo). And as Russell described very well, " they are cut to fit as if you are reaching up". Men back in time worked in their coats. Fred Astaire , Train conductors. Farmers. Ship captains. Doctors.
It is very practical. As in "practice".
From 5 to 9 on the draft is the key. The regular draft from 5 to 9 is 1". On the long undersleeve it is 1-1/2". This ups and outs the undersleeve as if you are reaching. It does not pull up the coat. This explains very well the practical beauty of a high armhole.
Great example below.