  Several theoretical groups describe the antikaon-nucleon interaction at low
energies within approaches based on the chiral SU(3) dynamics and including
next-to-leading order contributions. We present a comparative analysis of the
pertinent models and discuss in detail their pole contents. It is demonstrated
that the approaches lead to very different predictions for the $K^{-}p$
amplitude extrapolated to subthreshold energies as well as for the $K^{-}n$
amplitude. The origin of the poles generated by the models is traced to the
so-called zero coupling limit, in which the inter-channel couplings are
switched off. This provides new insights into the pole contents of the various
approaches. In particular, different concepts of forming the $\Lambda(1405)$
resonance are revealed and constraints related to the appearance of such poles
in a given approach are discussed.
