That was clearly a joke. It means to read that you have to equip the Masamune (which doesn't exist in FFX-2. For that matter, no specific weapon does) and then fight, I presume, one million Shuyins. This mocks the typical outlandish rumors (most commonly seen applied to FFVII) where one has to do all manner of ridiculous, impossible, and otherwise time-consuming tasks in order to bring about something that can't actually happen.