  Let $S^{\log}$ be a locally Noetherian fs log scheme and
$\blacklozenge/S^{\log}$ a set of properties of fs log schemes over $S^{\log}$.
In the present paper, we shall mainly be concerned with the properties
"reduced", "quasi-compact over $S^{\log}$", "quasi-separated over $S^{\log}$",
"separated over $S^{\log}$", and "of finite type over $S^{\log}$". We shall
write $\mathsf{Sch}_{\blacklozenge/S^{\log}}$ for the full subcategory of the
category of fs log schemes over $S^{\log}$ determined by the fs log schemes
over $S^{\log}$ that satisfy every property contained in
$\blacklozenge/S^{\log}$. In the present paper, we discuss a purely
category-theoretic reconstruction of the log scheme $S^{\log}$ from the
intrinsic structure of the abstract category
$\mathsf{Sch}_{\blacklozenge/S^{\log}}$.
