What imperial steps did Japan take to secure its position as a world leader during Tokugawa rule?

The unification of Japan began with the military conquests of Oda Nobunaga and consolidation efforts of Toyotomi Hideyoshi. After Hideyoshi's death, there was a power struggle between Tokugawa Ieyasu and Ishida Mitsunari. This culminated with Mitsunari's defeat at the Battle of Sekigahara (1600). Tokugawa Ieyasu became the unquestioned ruler of Japan after he defeated the last of the Toyotomi loyalists at the Battle of Osaka (1614 & 1615).