  A new spectrometer system was designed and constructed at the secondary beam
line K1.8BR in the hadron hall of J-PARC to investigate $\bar K N$ interactions
and $\bar K$-nuclear bound systems. The spectrometer consists of a high
precision beam line spectrometer, a liquid $^3$He/$^4$He/D$_2$ target system, a
Cylindrical Detector System that surrounds the target to detect the decay
particles from the target region, and a neutron time-of-flight counter array
located $\sim$15 m downstream from the target position. Details of the design,
construction, and performance of the detector components are described.
