Does anyone know what the grid etching on the wusthof blades stand for? I just bought some Wusthof Culinar knives and noticed the squares are in different locations. And the location of the blacked out squares on the photos on the Wusthof website : http://www.wusthof.com (main photo on homepage) are different to the ones on my actual knives. Do these stand for production batches or something? Any ideas?