The Mongol invasions brought with them a need for swords also suited for hand-to-hand combat and the smiths began manufacture of shorter blades to meet this need. It was during the Muromachi period that the "katana" and "tantō" came into being. By the sixteenth century, Japanese bladesmithing had become so renowned throughout Asia that the Japanese turned to large scale manufacturing of swords as an export to China. Smiths at Sakai also crafted knives for cutting tobacco, which had been introduced by the Portuguese. The Sakai bladesmithing industry received a major boost from the Tokugawa shogunate (1603–1868), which granted Sakai a special seal of approval and enhanced its reputation for quality.