The Sphere Grid found in Final fantasy X shows a departure from the normal formula of character development. Where before you had a character with certain attributes that were stronger or weaker than other characters, due to their "Class". Now with the Sphere Grid, you have the ability to develop each of your characters as you see fit to do so.

In the Sphere Grid, each character has a certain part that is considered their default grid. For Example, if you followed Yuna's grid, you would travel down the left side of the grid. But you do not have to keep to this path set out. There are several intersections in each characters grid, that with the right sphere, can go into another characters path. You might begin Tidus in his grid, which gives him abilities to speed the party, and slow the enemies. But shortly after beginning, he has a intersection with Auron's grid. Instead of continuing down his path, he can move over to Aurons, and gain more strength and damage enhancements.
There are also spheres that will allow you to jump across the grid, to other locations, though these are not seen until well into the game. This is an ideal way of creating a party fit to what you want it to be. It was met with great success, and has led into other titles having a similarly "open development for your characters.
Moving around the Sphere Grid requires AP. This is achieved after battles, but it is different than before. A player must basically perform an action within the fight, in order to gain AP. You will even get AP, if you miss in an attack. But if your character does not participate, they will not gain AP. The only time this is exempt is if Yuna summons an Aeon. If the Aeon defeats the enemies, without anyone else fighting, only Yuna gets AP. There for, summoning should be held out until the final round or so of battle.

When you gain enough AP, you will gain a Sphere Level. This will move you along the Sphere Grid. with each Sphere Level, you will be allowed to either move forward one space, or backwards up to four spaces. when you land on a new node, you then have the option of placing a sphere there. This is of course if you have the right sphere. Say Tidus lands on the Haste Sphere. You will need a "White Magic Sphere" to activate it. You can also activate any sphere adjacent to the one you are on. For example, after Tidus activates Haste, he has the ability to activate his Accuracy Sphere right by it.

This might seem a bit intimidating at first, but you will soon get the hang of it. Below is a list of the spheres you can find, and what they are for.

	HP Sphere	Adds HP to character
	MP Sphere	Adds MP to character
	Atk Sphere	Increases attack damage
	Mag Atk Sphere	Increases magic damage
	Def Sphere	Increases defense
	M Def Sphere	Increases magic defense
	Agility Sphere	Increases Agility
	Accuracy Sphere	Increases Accuracy
	Evasion Sphere	Increases Evasion
	Luck Sphere	Increases Luck
	Skill Sphere	Activates Skill Nodes
	Ability Sphere	Activates Ability Nodes
	White Sphere	Activates White Magic Nodes
	Black Sphere	Activates Black Magic Nodes
	LV. 1 Keysphere	Opens LV. 1 locks
	LV. 2 Keysphere	Opens LV. 2 locks
	LV. 3 Keysphere	Opens LV. 3 locks
	LV. 4 Keysphere	Opens LV. 4 locks

There are also two special spheres found within the game, that will grant special abilities on the grid. The first is a Clear Sphere. What this one does, is removes any stat sphere on the grid. when removed, that stat boost is also removed from any player that has activated it. Once it is removed, you can then place any other stat enhancing sphere in its place. For example, you can remove a +1 Agility boost from Tidus, and replace it with a +4 Agility Boost. This will then affect anyone who has activated the node so far. Not too bad of an idea really. But do not look for these, until further into the game.
The second is the Blue Sphere. This sphere has actually several different types. Each type is extremely useful on the grid.

	Return Sphere	Return to a previously activated node.
	Friend Sphere	Warp to another characters location on the Sphere Grid.
	Teleport Sphere	Warp to any activated node on the Sphere Grid.
	Warp Sphere	Warp to any spot on the Sphere Grid.

Below I have sectioned out each characters grid, so you can easily track their paths. Remember, that it is completely up to you where your characters go. The paths are specifically designed for the character traveling them, but that does not mean that you have to do it that way! Be creative, and try out different things. You will be amazed at what you can do with it.

	Tidus is on the upper portion of the sphere grid. Right off the bat, he will begin learning such support spells as Haste and Slow. As he progresses the grid, he will gain a great deal of useful support abilities as well. His major role is to quicken the parties moves, or to reduce the enemies. By the time he reaches the end of his portion of the grid, you should be able to send him to any other grid you wish. You can either go with a more magical aid, by going with Yuna or Lulu. If you want a more powerful fighter, head over to either Wakka or Auron.
	Auron's grid sits right between Tidus and Wakka. As he travels through his grid, he will gain a massive amount of strength and HP. He will also acquire a lot of "break" abilities to hinder enemies attacks and defense. Once he has finished his grid, it would be wise to go straight into Tidus's. This will give him a great boost in speed and agility to go with the powerhouse he already is.
	In the sphere grid, Wakka occupies the right side. On his travel through it, he will gain a lot of status attacks, and a few spells to drain HP?MP from his enemies. Once he finishes his portion of the grid, you can send him into Auron's grid for more damaging attacks, or into Tidus's for a faster hitter.
	Kimahri is started right in the of the sphere grid. He also has the smallest grid of the group. Once you have completed his grid, you can move him into any other grid, and still not go wrong. If you want a magic user, head into one of the ladies grids, if you want a powerful striker, head into Wakka, Auron, or Tidus's grids.
	Yuna's position on the grid is down the left side. She will learn great recovery and defensive spells along her journey. Ultimately she will become a major player on the field. Not only can she cure status effects, restore HP, she can also reduce damage from physical and magical attacks. Once she learns Holy, and has finished her grid, you might want to continue her magical stats, by placing her into Lulu's grid. This will allow her more ability to damage enemies with her magical talents.
	Rikku's grid is right below Yuna's. Although Rikku will gain little physical prowess on her travel, she can easily steal from her enemies with her higher agility. Steal and mug will benefit the group in many ways. Bribe is great for getting rare items from enemies as well. Considering her fairly weak attacks, it would be wise to send her into either Lulu or Yuna's grid. This way, she can either help restore the party, or damage the enemies with magic.
	Lulu occupies the lower right side of the sphere grid. Her magical attributes will raise as she goes, thus increasing the damage of her spells. You should also consider learning Osmose and Drain, when they open up. When you finish Lulu's grid, you should send her over to Yuna's, so she can also gain some healing magic as well.