A Split Back Yoke
The yoke is the panel of fabric below the back of your collar. This panel of fabric is quite often one single piece but unfortunately this usually results in an ill-fitting shirt. The best made shirts will always have a split back yoke. This takes much more time and effort to tailor but the difference in fit is well worth the added expense.
- See more at: http://tmlewin-blog.com/2014/05/how-to-spot-a-good-quality-shirt/#.dpuf