Board Thread:General Discussion/@comment-4957813-20131130185522/@comment-24185694-20140605165635

Sternritter M wrote: Chapter 109, page 17

http://www.mangapanda.com/94-563-16/bleach/chapter-109.html

Despite what it says, It couldn't possibly have been in shikai because he has never released it, due to not knowing its name. When ichigo learned Shikai he called out Zangetsu's name and from there on out, it remained in its shikai. Kenpachi on the other has been carrying an assachi all this time.

Furthermore, it seemed like what Kenpachi said to Ichigo stemmed from Ignorance. At the time, Kenpachi hadn't fully acknowledged his Zan and view Zans in general as mere tools.