Actually, a properly ground yanagi supposedly has the slight convex on the "flat' side with flats at the very edge and spine and down at the tip and the typical Japanese blended multi faceted grind on the bevel side. If you watch a video from say Korin on how to sharpen a yanagi, you will see that they do the "flat. from the middle of the blade rode/bevel up to the shinogi line first and then raise the spine knife VERY slightly on the stone to do from the middle of the rode to the edge second and then blend. Those two facets are so subtle that they do this merely by where the place their fingers on the blade and apply downward pressure when they are sharpening. Some folks may also put a microbevel on the flat side to give the edge a bit more beef. Grinds on kitchen knives are very subtle because you typically don't have a lot of material thickness to work with.
