Turtling is a gameplay strategy that emphasizes heavy defense, with little or no offense. Ostensibly, turtling minimizes risk to the turtling player while baiting opponents to take risks in trying to overcome the defenses. In practice, however, games are often designed to punish turtling through various game mechanics. Consequently, while turtling strategies are usually simple enough for novices to learn and are effective as such, they are easily defeated by experienced players who understand the game's methods to counter turtling.
As a metaphor, turtling refers to the defensive posture of a turtle, which retracts its limbs into its hardened shell for protection against predators. A player who concentrates on defense is said to behave like a turtle, reluctant to leave the safety of its shell for fear of suffering a lethal attack.
In the world of fighting games, especially those of the 2D variety, a turtle style of play is a defensive style that focuses on patience, positioning, timing, and relatively safe attack options to slow down the pace of the game and minimize the number of punishable mistakes made during the course of the match. This style can be very useful in timed matches, as it allows a player to deal a negligible amount of damage to an opponent, and then win the match by running down the clock. If available, players can turn off the timer to prevent such a strategy. Turtling can also be used to force an opponent into making punishable mistakes while minimizing the damage one takes, this is specially true when using projectile-heavy characters that are able to both maintain the pressure and stay out of harm's way. In few other cases, turtling can be an effective strategy to minimize the offensive effects of temporary buffs.
Game mechanics can be designed specifically to discourage turtling. For example, super attack meters may build up faster when using aggressive attacks, and may even decrease as a result of blocking or not attacking. Games can also offer a greater variety of possible hit locations (e.g. utilizing mix-ups) that make it more difficult for a defender to successfully guess how to block or counter. Super Smash Bros. has a character's shield shrink as it is used and takes damage, but it will grow back to full size when not in use. If the shield shrinks too much, it will burst and stun the player for a short period of time.
Real-time strategy games
A turtle strategy is commonly used in real-time strategy video games. When turtling, the player protects their territory, to the exclusion of creating forces for attacking the enemy. A turtling strategy may work because it forces the opponent to be more aggressive and constantly force him to attack the turtling player until the map is mined out and the opponent does not have any resources to replenish their forces. The most common way to turtle is to build large numbers of towers, turrets, and other defensive structures to fire on enemy units. Turtle armies may also incorporate large groups of artillery units to extend effective range and prevent opposing artillery units from attacking with impunity.
The turtling strategy has some major weaknesses. First, many games have units which out-range defensive buildings (catapults, artillery, etc.) and/or short-range units which are fast enough and tough enough to rush the defenses. The turtling strategy may then collapse (especially if overly dependent on choke points) as the more aggressive player destroys one group of defenses, destroys resource-gathering and unit-building facilities in that area, and then attacks another set of defenses, etc. (assuming that the attacker has been building reinforcements in the meantime). Another serious weakness of turtling is that it prevents the turtler from spreading across the map to acquire additional resources and therefore lets the enemy use these resources to build more and often better offensive units. The seriousness of this disadvantage varies: it is most serious on maps where there are many resource patches and few opponents competing for them.
The economic model employed by the game can also be a factor in how serious the disadvantage can be. For example, in the Supreme Commander series the game relies on Mass and Energy, both of which are literally infinite (the real economic factor is the income per second), and with all nations of players being able to produce a not only sufficient, but plainly extreme amounts without relying on any resource deposits found on the map. In Command & Conquer: Red Alert, the economy relies solely on ore and gems; while both resources are finite and can be exhausted, the ore in the game is a renewable resource and if left alone will regenerate from a fixed position and spread. The slow rate of ore regeneration does means that a player must expand to secure additional ore supplies in order to have a secondary source to switch to once the primary ore supply reaches the point of exhaustion. In WarCraft II, a player's economy relies on gold, lumber, and in some cases oil, all of which are nonrenewable; therefore a failure to expand and secure these resource early can prove fatal to a player later in a match, particularly if the player expends forces to secure resource stockpiles that have already been partially or heavily mined, harvested, or refined by other players. The lack of any renewable resources in this game also means that the turtling players must give careful consideration to the matter of whether or not to effect repairs, as the inability to replenish supplies means that any material gathered that is used for repair can not be put toward new structures, units, or upgrades that may be necessary later in the game.
Under competitive multiplayer conditions starting resources are often limited, and the turtling strategy involves devoting them all to defense while disregarding other objectives, the most important of which usually being to attack and secure other sources of income. While the turtle builds up his defensive shell, the "attacker" is free to take control of the rest of the map, providing them with an abundance of resources with which to build up a large force (including artillery which can outrange defensive structures, and superweapons, if applicable) and invade from all sides.
Turn-based strategy games
Turtling is also possible in TBS (turn-based strategy) games. It is probably best explained by a classic TBS game such as Risk. A player will simply accumulate armies in one place without attacking other players. As the game progresses, the turtle becomes stronger but other players will not risk attacking in fear of getting weak for no benefit. The turtle exploits the selfishness of other players to its advantage until it is powerful enough to start taking them out one by one. Solutions have been proposed to take the turtle out by cooperation as suggested by Ehsan Honorary.
The situation is similar in resource-based games as well. TBS games have much more scope for research than most RTS (real-time strategy) games, so the objective is usually to spend the minimum of resources on combat units and to focus on research and economic development until the player is in a position to build a large force of advanced units.
Turtling in TBS games has the major weaknesses of turtling in RTS games: vulnerability to powerful mobile forces, and failure to expand and claim additional resources. It may have additional weaknesses depending on the game. For example, in the Civilization series, resource gathering areas are outside the city walls and attackers can drive citizens away from them, destroy any improvements made in these areas (roads, irrigation, mines) and ultimately cause the population of the city to decline due to starvation. In Master of Orion II, one tiny combat ship can blockade all colonies in a star system until it is destroyed or forced to retreat, and this may cause starvation in all colonies of that star system.
Turtling mechanisms also vary widely in TBS games. For example, in the Space Empires series interstellar travel is only possible via "wormholes" and the running costs of fleets are fairly low, so turtlers treat some systems on the edge of their territory as choke point, keeping their fleets in these locations. They may also build space stations and defenses on the wormhole itself, while leaving little to no defenses on systems deeper inside their locked territory. In Master of Orion II, a ship can travel to any star which is within its travel range and the running costs of large fleets can be ruinous, so turtlers rely more on the wide variety of planet-based and orbital defensive buildings, plus a small mobile force to eliminate blockaders. In the Civilization series, city walls give defenders a major advantage in low-tech combat, so turtlers keep their forces within the walls unless there is an urgent need to destroy enemy units which can fire over city walls (generally the late game, higher tech units) or are threatening to starve the city to death. In Sword of the Stars each race uses different method of FTL travel some of which encourage turtling.
First-person and third-person shooter games
In first-person shooters (FPS), turtling is used in team-based games such as capture-the-flag games or zone control. By putting a disproportionate number of players on the defensive, guarding their team's base, flag, or a pivotal strategic point, the turtling team can overwhelm an enemy team with a balanced offense and defense by outnumbering their offense. Likewise, they can withstand a "Zerg" or rush by the other team. Using turtling is generally a temporary strategy at best, since by using the majority of their team to defend, they have few players to go on the offensive and accomplish whatever goals are required for victory, or used after gaining enough points to ensure victory without the other team scoring in such a game type and waiting out the time limit. Camping is also considered a turtling tactic.
MMORPG and CORPG games
In the instanced battlegrounds of World of Warcraft, "turtling" refers to a situation in which both sides have obtained the other side's flag. Since neither side can "cap" (capture) the opponent's flag without first recovering their own, a team may "turtle", or commit all of its team members to defense. This strategy originally could not achieve a victory, but it almost ensured against a defeat, as the turtling team will always maintain numerical superiority over the non-turtling team, unless the non-turtling team brings the flag carrier with them, which is an enormous risk. Now, the capture the flag style battlegrounds feature a match timer, and the team with the most flag caps will win, allowing one team to capture 1 or more flags and turtle for the rest of the game. In a more commonly "turtled" battleground, Alterac Valley, any attempt by either side to commit large numbers of players to defense thereby prolonging the game longer than usual is also considered "turtling". Debate exists here as well about what is defending and what is turtling. When one side resorts to positioning more players on defense, it does so claiming that it is delaying the opposing side so that their players on the offense can push forward, while the other side claims that the "turtlers" are deliberately trying to prolong a game that they have little chance of winning, usually because the side that most often "turtles" are losing. In that instance, before game servers were grouped in a fashion ensuring sufficient population, the player imbalance between the Horde and Alliance factions in the game at large often meant that if the larger-population faction prolonged the game sufficiently, as players left out of boredom the smaller faction's players would not be replaced, allowing for a zerg rush once the teams were sufficiently out of balance.
Tabletop miniature games and strategy board games
Turtling is also a strategy used in many non-computer games as well. In tabletop miniature combat games victory may be determined by the amount of opposing units destroyed. By waiting for the opponent to make the first move, a tactical advantage can be gained in many systems. For this reason, many game systems have implemented a victory system involving territorial control to combat the effects of turtling. Turtling is also a strategy in many strategy board games, the strengths and weaknesses of which are similar to those of turtling in real-time or turn-based computer strategy games.