A turn-based video game is a video game that incorporates a turn-based style of combat or battle system, where -- in battle -- characters take individual turns committing an action of play. When each character has taken a turn, the round is over and the turns start over.
For a turn, a character usually has the option of inflicting an attack, casting a magic spell, using an item (on self or on another character), or attempting to flee. This style of combat is most typically found in role-playing video games, where characters travel in parties and there can be multiple turns between party members and enemies.
Players of turn-based games have a period of time (can be either finite or infinite) to analyze and think before committing a character to a particular action. This slows down the gameplay in favor of developing an optimal strategy.
But not every turn-based video game has the same style of turn-based combat. There are several different types of turn-based play that have been developed to offer different speeds of play and different methods of analysis.
Traditional Turn-Based
Traditional turn-based combat is the oldest battle system for turn-based play, where players randomly encounter enemies and open up a new screen of battle between party members and a group of enemies.
In this type of battle, the player selects the actions (such as fight, cast a spell, or use an item) for all of the party members up front and none of the actions start until they have all been chosen. The character with the highest status for agility or speed then goes first and follows down the line with the character or monster with the lowest stat.
The first Final Fantasy game (developed by Square Co., Ltd. in 1987) implemented this system, but no game has used it since the development of more complex systems.
Active Time Battle (ATB)
An active time battle system adds an element of timing for commands. Instead of selecting all of the characters' commands at the start of each round, the player selects the commands during the progress of battle.
The characters then cast their turns when the ATB gauge is full. As soon as they perform the action, the gauge depletes and refills according to that character's agility or speed status. As a result, there are no finite rounds. Characters or enemies may take multiple turns in one round.
Final Fantasy IV (developed by Square Co., Ltd. in 1991) was the first video game to use this system, but the ATB gauge was not incorporated until Final Fantasy V in 1992.
Conditional Turn-Based (CTB)
Conditional turn-based systems still use much of what the ATB system introduced. There are no distinct rounds and characters with higher speed will take more turns than others. However, certain spells and character abilities can alter the order of the characters' turns, as some abilities take longer to recover from than others.
There is also no ATB gauge and all action stops when the player decides on a character's action. This is far less rushed than the ATB system and allows the player more time to think before acting.
The first video game to incorporate CTB was Final Fantasy X (developed by Square Co., Ltd in 2001), and it's still found in recent role-playing video games, such as Lost Odyssey (developed by Microsoft Games in 2008).
Tactical Turn-Based
A tactical role-playing video game combines both elements of turn-based play and tactical strategy games. Like typical turn-based play, players control party members' actions for each round, but the game also forces the player to consider tactical movement of the party members, usually on some form of grid.
Two recent examples of this style of turn-based combat are Fire Emblem: Shadow Dragon (developed by Intelligent Systems in 2008) and Disgaea 3: Absence of Justice (developed by Nippon Ichi also in 2008). The Last Remnant (developed by Square Enix in 2008) implemented this combat system also, but without a grid.
Active Dimension Battle (ADB)
In 2006, Square Enix attempted to combine both the ATB system and real-time combat for a new turn-based style called active dimension battle for Final Fantasy XII. Like tactical turn-based combat, players do not randomly encounter enemies but can choose which enemies to engage. But unlike the typical tactical style, there is no set grid.
When in battle, each character has an ATB gauge, which stimulates rapid combat and decision-making, but players can pause battle at each character's turn -- like CTB -- by bringing up the character's battle menu.
In essence, it's really a real-time battle system in a turn-based disguise.
Future Turn-Based Variations
Final Fantasy XIII will have a new turn-based system called the command synergy battle system. However, since Square Enix has only released a demo with a year-old-build and it's still over six months until its release in Japan, any discussions of the elements of the new system are only conjecture and speculation.
Visit the following link for a list of all turn-based games, including all future games to be released.