vrule align with top of the text using multicols

Question

My MWE is:

\documentclass{book}
\usepackage{showframe}
\usepackage{lipsum,multicol}
\pagestyle{empty}
\setlength{\columnseprule}{2pt}
%\setlength{\multicolsep}{-10pt}
\begin{document}

\lipsum[1]

\begin{multicols}{3}
\lipsum[1-10]
\end{multicols}
\end{document}

I would like to align rule with top of the text. (see the example image).

Answer 1

The multicols environment uses \topskip before typesetting the columns. Setting topskip=0pt is a (possible) solution.

Modifying \multicolsep does only affect the total spacing above multicols environment, but not the internal skip.

\documentclass{book}
\usepackage{showframe}
\usepackage{lipsum}
\usepackage{multicol}
\pagestyle{empty}
\setlength{\columnseprule}{2pt}
\begin{document}

\lipsum[1]
\begin{multicols}{3}
\topskip=0pt
\lipsum[1-10]
\end{multicols}
\end{document}