  We use the dense HectoMAP redshift survey to explore the properties of 104
redMaPPer cluster candidates. The redMaPPer systems in HectoMAP cover the full
range of richness and redshift (0.08 $< z <$ 0.60). Fifteen systems included in
the Subaru/Hyper Suprime-Cam public data release are bona fide clusters. The
median number of spectroscopic members per cluster is $\sim20$. We include
redshifts of 3547 member candidates listed in the redMaPPer catalog whether
they are cluster members or not. We evaluate the redMaPPer membership
probability spectroscopically. The scaled richness ({\lambda}rich/S) provided
by redMaPPer correlates tightly with the spectroscopic richness regardless of
the cluster redshift and appears to be a better mass proxy than the original
richness, {\lambda}rich. The purity (number of real systems) in redMaPPer
exceeds 90% even at the lowest richness; however, there is some incompleteness.
Five massive galaxy clusters (M $\gtrsim 2 \times 10^{13}$ M$_{\odot}$)
associated with X-ray emission in the HectoMAP region are missing from the
catalog.
