  Building on the work of K. Chiba (J. Algebra 263 (2003), 75-87), we present
sufficient conditions for the completion of a division ring with respect to the
metric defined by a discrete valuation function to contain a free field, i.e.
the universal field of fractions of a free associative algebra. Several
applications to division rings generated by torsion-free nilpotent groups, skew
Laurent series and related division rings are discussed.
