Instructions
Playing Sphere Break
Select one of the four golden coins surrounding the sphere. Each one has a number on it.
Tag a border coin. It also has a number. If the sum of the golden coin and the border coin is a multiple of the number in the sphere, then that border coin gets flipped over. The goal is to flip over as many border coins as you can in a limited number of turns.
Mark a second border coin if the sum of the first coin and the golden coin is not a multiple of the sphere's number. Add as many border coins as are available to create your multiple.
Repeat this process until you run out of turns or meet the game's quota. The turn-limit and quota vary from challenge to challenge.
Winning the Luca Competition
Proceed through the game until you arrive at Luca. A Sphere Break Competition is going on.
Walk to Square, which is on the northern end of town. Speak with the guy walking around to initiate a Sphere Break game. Next, speak with the blond man leaning against the fence and beat him.
Go to the Bridge, which is immediately south of the Square. Speak with the old man to initiate another Sphere Break game. Once you beat him, you'll automatically enter the finals.
Defeat Shinra and you'll win the Lady Luck Dress Sphere.