If you say the words “Y-Seams” to many quilters you will see them cringe and make funny faces.
A Y-Seam occurs when three seams intersect. To sew them together you stitch three seams. The good thing is these seams are almost always straight so you are stitching three straight seams.
For each of the three fabrics at the intersection you start by marking the intersections of seam allowances as shown. When you sew each seam you will start stitching at the marked point and stitch to the end. I like to backstitch a few stitches so the stitching stays put while I stitch the other two seams.
Mark your intersections as shown then view the video to see how to piece the three seams.