  Non-Hermitian skin effect of Liouvillian superoperators in quantum open
systems can induce phenomena of non-trivial damping, known as chiral/helical
damping. While non-Hermitian skin effect and chiral/helical damping occur only
under open boundary condition, we propose an effect called information restrain
which does not rely on boundary conditions. We demonstrate that information
restrain is stable against disorder and is an intrinsic property of a type of
open quantum systems or non-Hermitian system. Then we define the strength of
information restrain $I_R$, which describes the ratio of different decay rates
of signal's strengthes along opposite propagation directions. Based on
information restrain, We can provide a simple and elegant explanation of chiral
and helical damping, and get the local maximum of relative particle number for
periodical boundary system, consistent with numerical calculations. In terms of
information restrain, we also illustrate the existence of correspondence
between edge modes and damping modes and deduce that there are many
chiral/helical transport properties in this 'information restrain' class.
