The Collaborative International Dictionary of English v.0.48:

Handy-dandy \Hand"y-dan`dy\ (h[a^]nd"[y^]*d[a^]n`d[y^]), n.
   A child's play, one child guessing in which closed hand the
   other holds some small object, winning the object if right
   and forfeiting an equivalent if wrong; hence, forfeit.
   --Piers Plowman.
   [1913 Webster]