I think the kanji says "Kagekiyo.".
Baba cutlery works (株 馬場刃物製作所) makes knives with that mark. http://www.baba-hamono.com/
(yeah... Their website sux.)
The reason i am not too sure is the reflected light on your photo makes the bottom of second word a little unclear, but it looks a little funny compared Baba's usual mark.
The knife your chef bought is a stainless one, right? Hard to tell from the picture, but.... Baba makes a nice one in Ginsanko steel, and this blade looks similar to it....at least to me. Hope this helps