"Walls are great for keeping your village safe and your enemies in the line of fire."
Wall placement is a key point in designing a well-defended village. Walls are the main fortification for defense and are capable of withstanding a great deal of damage from attacking enemies. However, the effectiveness of Walls is greatly lowered if they are not constructed to completely enclose the structures they are designed to protect. Any gaps in the continuation of the Wall structure will render it useless, as enemy Troops will simply walk through the broken area.
An exception to this rule is the funneling strategy, where a player deliberately leaves a gap in order to group troops together and subsequently take them out using the splash damage of defensive units such as Mortars or Wizard Towers. Alternatively (or additionally) you catch your intruders off-guard by filling the openings with traps such as Bombs or Spring Traps.
If there are 2 layers of Walls, the Wall Breaker's blast radius will affect both layers.
The main purpose of Walls is to hinder attacking ground (i.e. non-flying) Troops, allowing defenses to damage and kill attackers as they attempt to breach the Walls. Once breaches occur, the attacking Troops have free rein to destroy the defenses and other buildings within the Walls. Therefore when designing a defense, it is crucial that players do not to attempt to envelop their entire village within one big Wall. Instead, it is recommended that players design their Walls in layers or cells so that ground troops have to break through multiple Walls to attack the entirety of the village, while also providing the defenses more opportunity to repel the attack. Note that with this strategy there will inevitably be buildings that cannot be placed within the Walls; that is entirely normal and can even be used to your advantage by placing non-defensive and non-resource buildings such as Builder's Huts, Army Camps and Laboratories immediately outside the Walls to act as another layer for enemy Troops to fight through.
If a defender uses a double-walled design, Wall Breakerscan hit the inner Walls as well. This is because the unit's bomb inflicts damage to everything within a small radius of its detonation (area attack).
Attacking Archers and Wizards are capable of shooting over Walls and attacking the structures behind them. Defenders can use less-important buildings as a "buffer", delaying these ranged units' attacks on more important buildings. In this case, make sure that long-ranged defenses are within range and have ample opportunity to retaliate before these buffer buildings are completely destroyed and the attackers can advance to the Wall.
The defensive territory in which an attacker is not permitted to spawn Troops is shown in a white overlay after any building has been moved. An attacking player may be able to spawn Troops behind the Walls if any area gaps exist in this territory. Since every structure has an additional one square perimeter around which Troops cannot be spawned, avoid gaps of greater than two squares to prevent this from happening. Traps, decorations, obstacles and Hidden Teslas are exceptions and do not increase the defender's territory.
An outdated practice is to use single standing Wall struts to lure Wall Breakers; however, this tactic no longer works, as Wall Breakers will only target Walls that are two or more consecutive segments. This technique can, however, be used to extend the defender's territory, and thus the outer perimeter of where attackers may spawn Troops.
Wall Breakers only target Walls that completely or partially enclose buildings; they will ignore empty compartments and spikes.
A common mistake among beginners is the attempting to "close" Wall gaps with buildings, rocks, trees, decorations, etc. This does not work; Troops can walk right through the gap as though the obstacles weren't there. Only continuous Wall segments will deter ground troops.
Another common mistake made by new players is attempting to use the edges of the map as barriers, thinking that this will allow them to construct Walls on only two or three sides. This also is ineffective, as enemy Troops can always be spawned on the darker grass area surrounding the village, even though buildings cannot be placed there by the player.
Look for gaps or Wall segments that are lower levels than others. Also look for areas within Walls where people have positioned their buildings poorly. Be careful, however, as gaps can often be intentional and may contain Traps or Hidden Teslas. Make good use of Wall Breakers to penetrate Walls quickly. Attack Walls that are out of range of defenses, if possible.
Spiking will no longer work, so you can avoid decoys and distractions.
Once a section of a Wall is breached, Wall Breakers will ignore that section and attempt to find the next closest Wall that encloses a building. That section may or may not be behind the breached section.