The Shun Blue Steel line is made of Japanese san mai construction; with blue #2 carbon steel sandwiched between two layers of stainless steel for the ultra-sharp benefits of carbon steel without the additional maintenance. Blue #2 steel is hard and takes a great edge and you will see patina form right on the edge where the blue steel is exposed after use. You still need to keep these knives dry after use.
I loved this knife so much,so much. It took an amazing egde with very litle work and held it for a long time. It would stay sharp for days of heavy prep. Then one day when i was just sliceing bacon with it,i caught the tip of the knife slightly on my boos end grain maple board and the knife tipped i lost about 4 mm off the tip. It reshaped fine and still is hair popping sharp but it tipped so randomly and quickly during proper use that i would not recommend this knife to anyone. It’s by far the best shun knife out there the fit and finish are perfect but it just does not seem durable.