This is not a knitting magazine, so excuse the lack of makeup, frizzy ponytail, and bad wardrobe. Instead, focus upon my Chocolate Bolero, greatly influenced by Barbara G. Walker's Knitting From the Top. She thoroughly describes 3 different methods of seamless set-in-sleeves. In this body-first method, the sleeve stitches are picked up from the armholes of the finished body, and then knit in a series of short rows down to the cuff. It took several tries to pick up the perfect number of stitches and to successfully hide the short rowing, but it was so worth the sweat.
Then there's the simultaneous set-in sleeve method, similar to knitting a top-down raglan. It too involves short-rowing and picking-up, but to me, much easier that sewing seams, and way more stretchy. This is the Cute Cotton Cardigan for my nephew, who can now comfortably wave his arms around without the hindrance of seams. Now all I need are the perfect buttons.
What you're seeing here is a series of lifted increases to create a mock-seam at the armhole. Clever, isn't it? I may never sew a set-in sleeve again.