The edge looks like it's starting to show signs of being more ground in the middle than the heel and toe, leading to what I believe is a frown? Prior to this most recent session, the edge was almost perfectly flat from heel to toe, except for the slight curve upwards at the toe. This is what happened to my Dovo. I've been trying to correct my strokes to applying pressure only at the heel and toe, and using x-strokes and paying attention to to the heel and toe and trying to not over-grind the middle.
My stones are flat. Yes, I use the same stones on my kitchen knives, and I regularly flatten and bevel the stones. Especially when I sharpen razors, just not every time I touch up a knife.
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