This 230x54mm gyuto was forged with a TNT666 core. This is a very special and rare steel.
From Xerxes website I quote:
 
"The cutting layer consists of a special melt that was produced exclusively for Achim Wirtz (steel dealer and producer). Several years ago, Achim Wirtz had a small quantity (approx. 80 kg) of this steel produced as a test melt as part of a university project. Since then, a few blades made of this material have occasionally appeared. Now there is a new edition of the former test melt, but this time only 400 kg of the steel were produced. So it remains a highly exclusive material.
 
TNT666 is an extremely wear-resistant, medium-alloy tool steel with a high level of hardness that can be achieved. Its wear resistance can easily compete with that of 1.2562. The steel forms extremely hard titanium-niobium and tungsten-chromium mixed carbides. At the same time, the total content of the special carbides is still low enough so that fine cutting edges are also possible. A rare material with very good properties.
 
C = 1,21 %
P <= 0,01 %
S <= 0,01 %
Si = 0,26 %
Mn = 0,29 %
Cr = 0,27 %
W = 0,62 %
Ti = 0,59 %
Nb = 0,61 %"
 
Being a friend of Achim, I got the very last bar of TNT666 that was probably ever sold while on a visit to his shop. It is nowhere to be found nowadays. The steel is EXTREMELY wear resistant. It far exeeds Apex Ultra for example. Unlike any steel I've worked with.
Enough about the core, the cladding is twist suminagashi made from O2 and wrought iron. The deep etch gives some incredible detail and it looks 
The handle is olive wood. Total weight is 166g and it is a light midweight grind, not too thin on the tip but a razor thin cutting edge.