They are excellent knives. I bought some in Norway. The middle layer is very hard steel and holds an edge well. However it it is brittle. The mild steel on the outer layers gives the knife its strength so it does not break.
Apparently, high quality knife steel is not that expensive. Around 60 years ago, I bought and Imperial sheath knife brand new for $1.00.
It had imitation bone plastic handles and the guard was a stamping but the blade itself was and is excellent. It is easy to sharpen and holds an edge. That is one reason that it irritates me to find a knife with poor quality steel.
I once bought a “Western” brand bowie which was really large and heavy and not cheap either. The steel was so poor that the edge actually bent when I was chopping at some hard wood.
Other Western brand knives were OK.