  We are interested in the three-dimensional quasilinear wave equations with
null condition. Global existence and pointwise decay for this model have been
proved in the celebrated works of Klainerman \cite{Klainerman86} and
Christodoulou \cite{Christodoulou86} for small smooth initial data. In this
work, we illustrate the precise pointwise asymptotic behavior of the solutions
for initial data posed on a hyperboloid and show that the decay rate
$v^{-1}u^{-1}$ is optimal for a generic set of initial data.
