\documentclass[12pt]{book}

\renewcommand{\baselinestretch}{1.5} 

\usepackage{tabularx}
\usepackage{multicol}
\usepackage{lipsum}
\usepackage[top=2cm,bottom=4.7cm,left=2.5cm,right=2.5cm,asymmetric]{geometry}
\usepackage{amssymb}
\usepackage{forloop}
\usepackage{titling}
\usepackage{graphicx}

\usepackage{fancyhdr}
\pagestyle{fancy}
\pagenumbering{arabic}
\renewcommand{\headrulewidth}{0pt}
\renewcommand{\footrulewidth}{0.4pt}
\fancyhead[EOC]{
\begin{tabularx}{1.\textwidth}{l X l l X}
 Partie Nr.:    & \multicolumn{1}{c}{ Spaßpartie \ }  &     & Datum, Ort:       & \rule{5cm}{0.15mm}    \\ [1.5ex]
 \hfill \\ [0.02 cm]
 Weiß:          & \rule{5cm}{0.15mm}            &           & Schwarz:          & \rule{5cm}{0.15mm}    \\ [1.5ex]
 \hfill \\ [0.02 cm]
 Zeitkontrolle: & \rule{5cm}{0.15mm}            &           & Zeitkontrolle:    & \rule{5cm}{0.15mm}    \\ [1.5ex]
\end{tabularx}
}

\addtolength{\headheight}{5\baselineskip}

\fancyfoot[EOC]{Spaßpartie}

\begin{document}

    \begin{center}
        \begin{tabular}{|r|m{3cm}|m{3cm}||r|m{3cm}|m{3cm}|}
            \hline
            \multicolumn{2}{|c|}{Weiß} & \multicolumn{1}{c||}{Schwarz} & \multicolumn{2}{c|}{Weiß} &\multicolumn{1}{c|}{Schwarz}  \\ \hline
            1         &           &   & 26        &           &   \\ \hline
            2         &           &   & 27        &           &   \\ \hline
            3         &           &   & 28        &           &   \\ \hline
            4         &           &   & 29        &           &   \\ \hline
            5         &           &   & 30        &           &   \\ \hline
            6         &           &   & 31        &           &   \\ \hline
            7         &           &   & 32        &           &   \\ \hline
            8         &           &   & 33        &           &   \\ \hline
            9         &           &   & 34        &           &   \\ \hline
            10        &           &   & 35        &           &   \\ \hline
            11        &           &   & 36        &           &   \\ \hline
            12        &           &   & 37        &           &   \\ \hline
            13        &           &   & 38        &           &   \\ \hline
            14        &           &   & 39        &           &   \\ \hline
            15        &           &   & 40        &           &   \\ \hline
            16        &           &   & 41        &           &   \\ \hline
            17        &           &   & 42        &           &   \\ \hline
            18        &           &   & 43        &           &   \\ \hline
            19        &           &   & 44        &           &   \\ \hline
            20        &           &   & 45        &           &   \\ \hline
            21        &           &   & 46        &           &   \\ \hline
            22        &           &   & 47        &           &   \\ \hline
            23        &           &   & 48        &           &   \\ \hline
            24        &           &   & 49        &           &   \\ \hline
            25        &           &   & 50        &           &   \\ \hline
            \multicolumn{6}{|c|}{ $\square$ Weiß gewinnt \hspace{3em} $\square$ Remis \hspace{3em} $\square$ Schwarz gewinnt } \\ \hline
        \end{tabular} 
    \end{center}

\end{document}