link to interesting blade

I think the description is incorrect .I think it's a laminate with VG-10 core , some softer stainless steel on the outside [420 like Fallkniven ?] and in between the two is a thin layer of nickel.
Yes, BUT....I keep thinking that if the line is just the effect of grinding down into the different under-layers, why is the line so weird ?,,,

It seems to me that with the sides as nice and flat as they are, that the result of grinding down past the inner wrapped layers would also result in a straight line?......right?
Two ways to get that effect:
The nickel is folded,sort of accordion style,overlapping itself,creating thicker and thinner areas. The outer layer is applied with the nickel between it and the core,as mete said. The folds in the nickel make the zig-zag effect.
The other way of getting this effect is to set up the san-mai (outer layer) with a washboard texture on the mating surface (like you were going to do a ladder pattern). When that is applied over the nickel layer the nickel will form thicker and thinner areas. The effect will be identical to the blade shown.My guess is that is how the manufacturer did these billets.