  The structure of $K^-$-condensed hypernuclei, which may be produced in the
laboratory in strangeness-conserving processes, is investigated using an
effective chiral Lagrangian for the kaon-baryon interaction, combined with a
nonrelativistic baryon-baryon interaction model. It is shown that a large
number of negative strangeness is needed for the formation of highly dense and
deeply bound state with kaon condensates and that part of the strangeness
should be carried by hyperons mixed in the nucleus. The properties of
kaon-condensed hypernuclei such as the ground state energy and particle
composition are discussed. Such a self-bound object has a long lifetime and may
decay only through weak interaction processes. Comparison with other possible
nuclear states is also made, such as kaon-condensed nuclei without mixing of
hyperons and noncondensed multistrange hypernuclei. Implications of
kaon-condensed hypernuclei for experiments are mentioned.
