Yugi's Sennen item is the Sennen "Millenium" Puzzle - It keeps the soul of Yami no Yuugi locked inside it. Yugi originally didn't have the final piece of the puzzle. Jounouchi, in a temper from earlier, threw the final piece he stole from the box into the river. Later, he jumps in to get the final piece. He returns it to Yugi's Grandpa, Sugoroku, who gives it back to Yugi. Upon completion, the Pharaoh's soul is unlocked.