The new battle system for FFXIII is revolutionary, inwhich it maintains a command system shown such as in other Final Fantasies, but implements a fighting system simliar to FFXII. It's purpose is to run ATB (Active Time Battle) in an organized manner with the command system that was mentioned earlier. Following his work on Front Mission and Final Fantasy X, Tsuchida (who is currently employed at SquareEnix) is taking charge of the battle system in Final Fantasy XIII project.

Picture Demonstration of Active Battle System (ATB)

Tsuchida who worked on the FFX project also was allowed to work as how he saw the battle system fit. SquareEnix recognized the need to speed up the input of the battle systems, which eventually lead to the development of the CTB (Count Time Battle System). In realizing that the command system could not be done away with quickly, he has developed the concept of entering multiple commands in order to generate a smooth like motion project by the FFXIII characters. It will now be possible to combine magics, while attacking with a variation of moves. The best way to put it is that it's sort of like entering combo's on the pad in order to achieve a specific move or action. This is what FFXIII will base their success on.

In the upper left hand corner of the screen, as shown in the first picture, indicates where the enemy is standing. This gives the player the ability not to just focus on one character, but be able to move swiftly around the screen with the new revamped Active Battle system. Tsuchida indicated to the effect that he wants the enemy not to be randomly encounter, but has a realistic feel to the game in the way that the player is being encountered. For example, being in certain areas, you may got shot at or trapped without realizing it. It's difficult to understand how this will be done, but if done right, FFXIII will have an advanced FFXII feel to it with more realistic scenories.

Finally, the additonal basics will be an improved menu interface and overclock system, somewhat similar to limit breaks, but more advanced to provide more excitement to the game. In mind, Tsuchida's intent is to create battles that will match the vigor of Final Fantasy's Advent Children. This, we will all have to wait and see.

My Resources:  Wikipedia - FF-XIII.org - IGN - Self Research - Other Various Sites