  Recently we have proposed mechanisms to explain origins of the charged lepton
spectrum as well as Koide's mass formula, on the basis of U(3)\times O(3)
family gauge symmetry. In this note, we review the basic ideas of these
mechanisms. Without technical details, and adding some speculations, we give a
sketch of the mechanisms, what the important points are and what assumptions
are involved.
  We adopt a known scenario, in which the charged lepton spectrum is determined
by the vacuum expectation value of a scalar field that takes values on 3-by-3
matrix. Within this scenario, we propose a mechanism, in which the radiative
correction induced by U(3) family gauge interaction cancels the QED radiative
correction to Koide's mass formula. We consider SU(9)\times U(1) symmetry
broken down to U(3)\times O(3) symmetry. This leads to a potential model which
predicts Koide's mass formula and the charged lepton spectrum consistent with
the experimental values, by largely avoiding fine tuning of parameters. These
are discussed within an effective theory, and we argue for its validity and
usefulness.
