Apparently Hattori actually manufactured the Nenox C1 & C2 Cleavers, or at least that's what I infer from this e-mail response from Koki at JCK, which a user on another forum posted in August 2005:
Nenox Chinese cleaver C1 and C2 has same blade material. Since Nenox company keep secret about their blade material. We can only get information about its blade material below.
C1 and C2 has same material Nenox S1. Nenox special stainless steel which has HRC60 and have strong protection for the rust and good durability.
C2 handle material is Black Stamina wood. C1 has stainless part on bottom of its handle, but C2 does not have that stainless part.
Since Hattori company takes time to make and finish each products, their quality are all great. And if you can use the knife properly, it is very rare that knife get broken.
But when these thing will happen, please let us know. We are located in near from Hattori company and Hattori company can fix Nenox knife. (It might cost some, but knife will be perfect after Hattori company fixed.)
Nenox company does not carry Dupont Corian handle of Chinese Cleaver.
They carry C1 (Quince wood handle), and C2 (Black Stamina Wood handle)
C1 Thin Blade Chinese Cleaver Our price will be $486.00
C2 Thin Blade Chinese Cleaver Our price will be $385.00