# Error if using square brackets

I'm trying to achieve the plot of plain brackets around a word.

in this manner:

\begin{titlepage}
\vspace*{0.4\textheight}
\noindent
\textcolor{white}{\Huge\textbf{\textsf{Recupero dei solai lignei storici\\\\[BOZZA \today]}}}
\end{titlepage}

I get an error from latex, no error if i remove th brackets.

What's wrong with him - or me... - ?