Am 14.10.2014 um 10:13 schrieb Andrea Valle <valle@di.unito.it>:

Dear list, 

As I have a book with many chapters, I’d like to reset footnote numbering at each chapter. 
How can I achieve this?
I’m looking here:
http://wiki.contextgarden.net/Footnotes

but can’t find a solution

I looked also at  \setupfootnotes but it says: 

way bytext bysection
Start numbering from 1 again at the start of every section? 

BTW on mkiv, so I guess I should use \setupnotation

Yes, you have to use the \setupnotation command to set every counter related setting for footnotes.

\setupnotation[footnote][way=bychapter]

\starttext

\dorecurse{10}
  {\chapter{Chapter #1}
   \dorecurse{10}{\input knuth\footnote{\input ward }}}

\stoptext

Wolfgang