  The axial vector meson $K_1(1270)$ was studied within the chiral unitary
approach, where it was shown that it has a two-pole structure. We reanalyze the
high-statistics WA3 experiment $K^- p\to K^-\pi^+\pi^- p$ at 63 GeV, which
established the existence of both $K_1(1270)$ and $K_1(1400)$, and we show that
it clearly favors our two-pole interpretation. We also reanalyze the
traditional K-matrix interpretation of the WA3 data and find that the good fit
of the data obtained there comes from large cancellations of terms of unclear
physical interpretation.
