In Yachatz we take a matza and brake it and take one piece of it and hide it as the Afikomen. The Afikomen is then put aside to found later. 

The Void Century is a part of history that has been erased by the world government in One Piece so no one can remember it. Why the world government would do this is a mystery, but there is a theory that if people remembered the void century, they might rebel. 

The history of this century is hidden in text scattered around the world on indestructable stone known as poneglyphs. Poneglyphs can either contain details on the history of a mysterious figure named Joy Boy or if you find a red poneglyph, it will help guide you to a treasure. This treasure being the One Piece, the most mysterious and valuable treasure of all.

haggadah Section: Yachatz