  We show relationships between uniform K-stability and plt blowups of log Fano
pairs. We see that it is enough to evaluate certain invariants defined by
volume functions for all plt blowups in order to test uniform K-stability of
log Fano pairs. We also discuss the uniform K-stability of two log Fano pairs
under crepant finite covers. Moreover, we give another proof of K-semistability
of the projective plane.
