As Finance Minister in 1871, Ōkubo enacted a Land Tax Reform, the Haitōrei Edict, which prohibited "samurai" from wearing swords in public, and ended official discrimination against the outcasts. In foreign relations, he worked to secure revision of the unequal treaties and joined the Iwakura Mission on its round-the-world trip of 1871 to 1873. Realizing that Japan was not in any position to challenge the Western powers in its new present state, Ōkubo returned to Japan on September 13, 1873, just in time to take a strong stand against Saigō's proposed invasion of Korea ("Seikanron").