Woodblock printing
It was the invention of efficient metal type casting that was Gutenberg's most important invention. Woodblock printing had been known in China for centuries, and Laurens Janszoon Coster and other Dutch printers developed moveable type before Gutenberg. It was innovations in type casting that made for Gutenberg's breakthrough of commercially printing. Although using matrices was a technique known well before his time, Johannes Gutenberg adapted their use to a conveniently adjustable hand mould, enabling one to easily and accurately cast identical multiple instances of any character.