How to Get Doors to Tomorrow on "Final Fantasy X"by Marilla MulwaneUpdated September 22, 2017
In "Final Fantasy X," Door to Tomorrow is an item used during weapon and armor modification. Doors to Tomorrow are used to give a weapon the "Overdrive -> AP" ability. That ability significantly increases the amount of Ability Points earned after defeating an enemy, but it prevents the Overdrive gauge from filling. In order to modify a weapon with the Overdrive -> AP ability, 10 Doors to Tomorrow are required. Doors to Tomorrow are dropped, bribed or stolen from enemies. The easiest way to get Doors to Tomorrow is through the Monster Arena. It is possible to earn 99 Doors to Tomorrow through the arena.
Go to the Monster Arena in the Calm Lands. The arena is located along the eastern stone wall. There is a crack in the wall that leads to the entrance of the arena.
Talk to the man at the door. He will explain how the Monster Arena works. Purchase capture weapons from the man and equip them to the characters.
Leave the Monster Arena. Wander around until your party begins a battle. Fight the enemies in the battle. When a character with a capture weapon gives the finishing blow, the enemy will be captured.
Capture every enemy in an area. For example, capture one of every enemy in Besaid. They are the Dingo, Condor and Water Flan.
Travel to five more areas and capture one of every enemy in the area. Each area has specific enemies found nowhere else in the game.
Return to the Monster Arena in the Calm Lands after you have captured one of every enemy from six areas. Talk to the man and he will tell you that you unlocked six area creations in the Monster Arena. You are awarded 99 Doors to Tomorrow. You can fight the creations you unlocked in the Monster Arena.
Capture weapons are weaker than nearly all the weapons in the game. It is best to capture enemies once your characters are leveled up enough to kill weak enemies will one hit of the capture weapon. Capture enemies in the early areas of the game, such as Besaid, Kilika and the Calm Lands. The enemies are easy to kill and there are fewer of them to find.
You do not need to purchase a capture weapon for each party member. Just buy one for Auron to kill hard-skinned enemies, Wakka for flying enemies and Tidus for fast enemies. If strong enough, Auron will kill magic enemies such as the flan.
Some enemies are rare, or only appear in certain sections of an area. Comb every bit of an area until the enemies are found. Run from battles with enemies you already captured if you do not wish to fight them again.