Semi-Yapp
The best explanation I've read of the terms yapp and semi-yapp comes from R. L. Allan's Nicholas Gray, which you can read here: "Meaning of Yapp." Long story short, think of yapp as the edge of the cover. A semi-yapp cover will wrap around the page edges, while a full-yapp cover wraps even farther, to the point of touching or thereabout. Imagine an old-style zippered Bible minus the actual zip. Or better yet, just look at this picture:
Above: The R. L. Allan Compact Text Edition of the ESV, with semi-yapp edge.
There are two factors at work here: the extension of the cover, and the curve. A full- or semi-yapp cover is not simply one that extends out past the edge of the paper. It also curves around, as if to cup the book block in its leather embrace. The Bible in the photos, an R. L. Allan ESV Compact Text Edition, gets things just right. When executed well, a semi-yapp edge adds some Old World elegance to a Bible.
When you compare the Bible to the hardback journal underneath, you can see how a semi-yapp cover delivers practical benefits. Not only does it feel nice in the hand, but it also offers protection to the gilded page edges. On a small Bible like this, I find it particuarlly attractive ... but in all honestly, I like semi-yapp in any size cover.
The downside? Some people find that the extra leather around the edge of the cover gets in the way when flipping pages. I haven't had much trouble in that regard -- but I don't often rush from text to text (on principle, not just because I'm slow). Your mileage may vary, so be advised.
J. Mark Bertrand is a novelist and pastor whose writing on Bible design has helped spark a publishing revolution. Mark is the author of Rethinking Worldview: Learning to Think, Live, and Speak in This World (Crossway, 2007), as well as the novels Back on Murder, Pattern of Wounds, and Nothing to Hide—described as a “series worth getting attached to” (Christianity Today) by “a major crime fiction talent” (Weekly Standard) in the vein of Michael Connelly, Ian Rankin, and Henning Mankell.
Mark has a BA in English Literature from Union University, an MFA in Creative Writing from the University of Houston, and an M.Div. from Heidelberg Theological Seminary. Through his influential Bible Design Blog, Mark has championed a new generation of readable Bibles. He is a founding member of the steering committee of the Society of Bible Craftsmanship, and chairs the Society’s Award Committee. His work was featured in the November 2021 issue of FaithLife’s Bible Study Magazine.
Mark also serves on the board of Worldview Academy, where he has been a member of the faculty of theology since 2003. Since 2017, he has been an ordained teaching elder in the Presbyterian Church in America. He and his wife Laurie life in Sioux Falls, South Dakota.