The leveling system in Final Fantasy X was the one of the most innovative systems to be used in any Final Fantasy game. It was based not on regular experience and leveling like most (older) Final Fantasy games, but on a large grid where each character could move around on. It's like a giant board game, basically. Whenever an enemy is defeated, the characters that played a role in the battle receive AP (Ability Points). At pre-set amounts of AP, your character gains a Sphere Level; that much is the same as the more classic leveling systems.

With the Sphere Levels, you can move forward on the Sphere Grid between certain key points, called Nodes. For each Sphere Level a character has, they can move one Node forward. You can also move three places backwards with a single Sphere Level, if need be. Whenever your character is on a Node in the Sphere Grid, he/she can then spend so-called Spheres to activate the Node they're on, or the one(s) adjacent to their current location. You need to use Spheres in order to activate Nodes, which can be gained by defeating enemies in most cases. Each kind of node has a corresponding kind of Sphere. For example, Power Nodes are activated by Power Spheres, and Ability Nodes are activated by Ability Spheres. When activating a Node, the character gains either those stat points or that ability.

Nodes

There are a few kinds of nodes found on the Sphere Grid:

• Power Nodes
• Magic Nodes
• Speed Nodes
• Luck nodes
• Ability Nodes

The Power Nodes increase Power-related attributes, Strength and Defense. Strength dictates the amount of damage a character can do with melee attacks, whereas Defense determines how much damage they take when hit by an enemy melee attack. Power Nodes can also increase the HP (Hit Points) of a character, increasing the damage they are able to take.

The Magic Nodes, as implied, relate to Magic attributes. There's Magic, which determines the amount of damage the character deals using magic attacks; and Magic Defense, which determines the amount of damage taken when hit by an enemy magic attack. Next to Magic offense and defense, the Magic Nodes can increase the maximum amount of MP (Magic Points) a character can have, meaning they are able to cast more spells before having to refill it at a save point or by using an ether.

Speed Nodes can increase Agility, or the speed a character has during battle, which is used to determine when their turn is in relation to the enemies and the other characters. Secondly, Speed Nodes can increase Evasion, the higher this value is, the bigger the chance that the character can evade an attack, causing the character not to take any damage. Thirdly, the Speed Nodes increase Accuracy, which determine how much of a chance you have to hit your opponent.

Luck Nodes are the rarest nodes you'll find, and increases your luck. Luck determines everything in a small way, the higher this value, the higher your luck; for example, you could get lucky and not get killed in a single hit by an overpowered enemy.

Ability Nodes are all unique, and each gives a specific ability to whoever activates the node. For example, your character can gain the magic spell "Fira" by activating the Fira Ability Node..

Locks

Locks on the grid prevent the characters from gaining various stats or abilities. Not to worry though, you can open these locks by using Key Spheres. There are four levels of sphere locks in the Sphere Grid, and you need a corresponding Key Sphere in order to open them. The level one locks often guard reasonably petty upgrades (although they're often somewhat better than the ones you can access straight away), while the level four locks protect the strongest abilities and attribute increases found on the Sphere Grid. Key Spheres can be found throughout the game, by killing enemies, opening chests, and by refining them from items. Naturally, the level one Key Spheres are the easiest to find, whereas the level four are the hardest.

Key Spheres can be found throughout the game, by killing enemies, opening chests, and by refining items into them. Naturally, the level one Key Spheres are the easiest to find, whereas the level four are the hardest.

Special spheres

Next to the regular Spheres and the Key Spheres, there are a number of Spheres that have another special function in the Sphere Grid. They can be divided into a few categories. The categories and their spheres are listed below.

Remote Activation Spheres

These spheres give whoever uses them the ability to activate a sphere another character already activated anywhere on the Sphere Grid.

• Attribute Sphere: Activates any Attribute-enhancing node (power, magic, etc.)
• Special Sphere: For Special abilities. (i.e. thief, flee, etc.)
• Skill Sphere: For Skills. (i.e. Power Break, Dark Attack, etc.)
• White Magic Sphere: For White Magic abilities.
• Black Magic Sphere: For Black Magic abilities.
• Master Sphere: Activates any sphere of any kind previously activated by another character.

Customisation Spheres

These spheres allow the user to create an un-activated attribute sphere at any empty node on the Sphere Grid (as long as they're adjacent to it). The spheres are:

• HP Sphere: Creates an HP +300 node.
• MP Sphere: Creates an MP +40 node.
• Strength Sphere: Creates a Strength +4 node.
• Defense Sphere: Creates a Defense +4 node.
• Magic Sphere: Creates a Magic +4 node.
• Magic Defense Sphere: Creates a Magic Defense +4 node.
• Agility Sphere: Creates an Agility +4 node.
• Evasion Sphere: Creates an Evasion +4 node.
• Accuracy Sphere: Creates an Accuracy +4 node.
• Luck Sphere: Creates a Luck +4 node.

Other Spheres

The following spheres are special spheres that perform a special function in the Sphere Grid. These spheres are:

• Clear Sphere: Turns an existing node into an empty node (used when you want to max stats, for example, by clearing a Strength +1 node and placing a Strength +4 node in its place).
• Return Sphere: Allows the character to return to any sphere they've previously activated.
• Friend Sphere: Allows the character to teleport to a node where another character is currently located.
• Teleport Sphere: Allows the character to teleport to any sphere previously activated by any character.
• Warp Sphere: Allows the character to teleport to anywhere on the sphere grid, whether it's activated or not.

Versatility

As it was hinted in previous paragraphs, Final Fantasy X's Sphere Grid system allows every character to learn each others abilities, and gain each others attributes (a character who learns "Fira" can eventually learn to "Steal" as well). In the first part of the game (oftentimes the time it takes most people to finish the basic story of the game), each character's specialized (the character's specializations can be found in the Bios section). But in time, you'll be able to get onto the path of another character and learn their abilities. What is a weak attacker in the first part of the game, can become a strong melee warrior in time, and the other way around. The possibilities are nearly limitless; this is one of the strongest points in the game.

European Sphere Grid

The European version comes with an extra in the Sphere Grid system: the Expert Sphere Grid. This Sphere Grid works the same as the original Sphere Grid, the difference is that it has a completely unique layout. You start with all your characters pretty much in the center. From there, you can steer any character down any path you like. You could turn Rikku into a White Mage, or Auron into a Thief, for example. Next to that, the paths are all interwoven, which means your characters can easily switch paths whenever you chose.

As the name implies, the Advanced Sphere Grid should probably not be used by new players of the game, since it's not too hard to make the wrong decision and make the game a lot harder than it should be. Note that once you've selected which Sphere Grid you want to use at the beginning of the game, you cannot switch to the other one. Another note is that the Advanced Sphere Grid has about fifty nodes less available for activation, which means you can't get stats as high as you could with the original Sphere Grid. So if you're intending on getting the highest stats possible, choose the original Sphere Grid instead.

Other additions to the Final Fantasy X Sphere Grid found in the the International / European edition are a few new abilities. These abilities are:

• Extract Power/Mana/Speed/Ability: These four abilities make the character throw an attack that has the same effect as the Distiller items.
• Full Break: The four Break effects combined into a single attack.
• Pilfer Gil: Steal Gil from target.
• Nab Gil: Steal Gil and damage the target.
• Quick Pockets: Use an item and recover quickly. Item version of Quick Hit.

Final Fantasy X's Sphere Grid system may be the most versatile leveling system in the history of Final Fantasy. It allows the characters to learn each others abilities, where former Final Fantasy games had their characters stuck in a specific class, with their attributes increasing only by a pre-set formula and sometimes items or weapons. It also is a great tool for the die-hard Final Fantasy fans and those who want to have total control over their character's stats to get the most out of them as possible. With FFX's Sphere Grid, any character can become as good (or bad) as any other character, and the way your character develops is completely in your own hands.