Hyakumantō Darani
The Hyakumantō Darani (百万塔陀羅尼), or the "One Million Pagodas and Dharani Prayers", is a famous large-scale commission of woodblock printing, the earliest recorded use of woodblock printing in Japan, though probably not the first.
Woodblock-printed books from Chinese Buddhist temples were seen in Japan as early as the 8th century. In 764, the Empress Shōtoku commissioned one million small wooden pagodas, each containing a small woodblock scroll (typically 6 x 45 cm) printed with a Buddhist text, the Hyakumantō Darani. These were distributed to temples around the country as thanksgiving for the suppression of the Emi Rebellion of 764. These are the earliest examples of woodblock printing known, or documented, from Japan. Several examples survive (see link below).
The printing was completed around 770 and cost such a colossal amount of money that printing technology did not become widespread and the production and distribution of books continued to rely heavily on hand-copying manuscripts.