Water (水(みず), Mizu), known as Aqua in the English version of Yu-Gi-Oh! The Sacred Cards is an Alignment.

It is strong against the Fire Alignment and weak against the Thunder Alignment.

It appears in the games Yu-Gi-Oh! Dark Duel Stories, Yu-Gi-Oh! The Sacred Cards, and Yu-Gi-Oh! Reshef of Destruction and is briefly featured in the manga. In the OCG and TCG, WATER and Aqua are the Type and Attribute versions of this Alignment respectively.