One Piece Chapter 51, page 17: Roronoa Zoro Falls Into the Sea

Zoro unleashes his ultimate attack, shouting, "SANZEN SEKAI!!" (3000 Worlds). The two swordsmen clash in a flash of light. As they pass each other, Zoro's two ordinary swords shatter into pieces. Zoro stands silently, realizing his defeat, thinking, "I lost... I'm no match for him... Never even thought about the possibility of losing... So this is... the strength of the world's strongest...!" With a quiet click, he sheathes his remaining sword, Wado Ichimonji.