Shavings of a mokkan (narrow, long, and thin pieces of wood strung together that were used to write on in ancient times) with words such as 'Otsuo' (Prince Otsu), 'Tsuo' (Prince Tsu) and 'Oji' (prince) were excavated from Asuka-kyo site.
飛鳥京跡から「大津皇」「津皇」「皇子」などの文字の見える木簡（もっかん）の削り屑が出土している。