Yiddish kop or Yiddisher kop (ייִדיש קאָפּ); lit. Jewish head, is an Yiddish expression. The latter is used when a person wants to indicate that Jews, of which mainly Ashkenazi Jews are meant, are smart (have a good head).
Only an Yiddish kop like Einstein can solve this.
by Cousin Chaim February 24, 2012