  We present the results of an X-ray spectral analysis of the northeast region
of the candidate supernova remnant G189.6+3.3 with Suzaku. K-shell lines from
highly ionized Ne, Mg, Si, and S were detected in the spectrum for the first
time. In addition, a radiative recombining continuum (RRC) from He-like Si was
clearly seen near 2.5 keV. This detection of an RRC reveals for the first time
that G189.6+3.3 possesses an X-ray-emitting recombining plasma (RP). The
extracted X-ray spectrum in the 0.6-10.0 keV energy band is well fitted with a
model consisting of a collisional ionization equilibrium plasma component
(associated with the interstellar medium) and an RP component (associated with
the ejecta). The spectral feature shows that G189.6+3.3 is most likely to be a
middle-aged SNR with an RP.
