not only the VG-10 but also the "nashiji" pattern with "ginsanko" steel (silver steel #3) core is stainless clad. Silver steel is stainless itself with high chromium content and otherwise white steel #2 in composition. However it has been great to sharpen on my sigma stones and is mostly indistinguishable from white steel. This is not true with a chrome-moly steel (harder to sharpen). I *think VG10 has more molybdenum. The saved money, $170 if you get the $50 165 santoku nashiji, is enough for quite a decent 3 stones!
a warning on tanaka's though, the cheaper varieties with the western style handle (what I can speak to).. if you have very big hands, the handle might seem too small. I can *almost palm a basketball (for a second or two anyway) and its fine for me, but it is smaller than average.