Two teams of 11 players have the objective to get the ball into the opponent's goal and prevent it from entering into their own.

Players are distributed in the field by forming horizontal "lines": goal, defense, middle (midfielders) and attack. In turn, the players are divided into longitudinal zones: right, left, center: right-back, center; left midfielder, striker

Depending on the number of players in each line we can talk about systems, we start counting from the goalkeeper. For example the system 1: 4: 4: 2, which means a goalkeeper, four defenders, four midfielders and two strikers. The best way to see the system is when a team is defending, as all players will be taking up their position in the given lines. In attack, positions are "lost" a bit following plays.

Phases of the game: We say that the team is on attack, when it has the ball. By contrast, the team is in defense when they don't have the ball. Depending on the stage, we have other sub-stages with their own objectives.

Teaching the tactic when starting: Considering the stages and sub-stages of the game, we can teach our players a set of principles and fundamentals of the game that can guide as tools when making decisions. These are the selected basic principles:

1. Support-free spaces. Free spaces favor the offense. Searching, recognizing and using free spaces to support the team. We must teach players to be patient and "expect" the ball in the designated areas, their positions, when we are attacking. If there are defenders in their areas we have to motivate them to move to these free spaces "independently" of where the ball is, because if they are occupying free spaces their teammates can pass them the ball. In the early stages of training it is easy to see players "abandoning" a good position in a free space to go get the ball. This should be the other way: the player must be in a favorable position and the ball should go looking for him. Keeping in mind that not all free spaces are supportive, there's no point being in my corner if the ball is near the opposing goal.

2. Players without the ball should move always. In attack, players of the team without the ball mark the style of play, if they are still it's easier to mark them and therefore the player that has the ball will not have many passing options having to drive it through, make a long pass, make an ineffective shot or lose it. However if the players without the ball are in constant motion they will cause the following situations:

1. Supports to the player who has the ball. They can take support-free spaces, searching for the free passing lanes (angles).
2. Support to potential ball receivers, (the 3^rd player) Players moving "away" from the ball area must support the players closest to the player with the ball, making the transition of the ball faster and safer from one area to another.
3. Create free space for other peers without defender. Many times the attacker moves into a support-free space and the defender follows him, if this is the case the attacker has two options: to distance himself from the defender and occupy a new space or, and this is difficult to understand by young players, keep dragging a defender away from the support-free space that another teammate could occupy to receive the ball this time without defender.
4. Generate situations of superiority (numerical, tactical, technical, fitness) in vital areas: two forwards against a defender, three forwards against two defenders, etc ...

As we have seen, playing without the ball defines the type of game: possession, shots, "irrational actions to see if I get lucky and get something," actions based on effective decision making after perceiving situations...

3. Thinking in the future. The faster action is usually the most effective. Players must move the ball as quickly as possible because the ball is faster than the player and doesn't get tired. Players without the ball must "read" the game, what's going on "My goalkeeper has the ball and he's going to goal kick. They must "foresee" the next steps "he's going to pass the ball to my right defender or to my attacking midfielder who is unchecked". They must also "write" the game they are playing and of which they are the protagonists through future decisions, moving to support the player with the ball or the next pass receptors, "if my midfielder receives ball, how could it be an option for him to pass it to me? " And finally they should continue writing history with its successive actions "if I pass the ball to my midfielder, I could pass it on to my left forward and then run into the frontcourt to support you with the completion, so I must monitor the movements of my striker when the ball is coming to my feet to control it and pass it as quickly as possible effectively. "After passing the ball, the work is not finished yet, we must keep moving to support the player with the ball and/or possible future pass receivers.

4. Keeping the ball. The team with the ball is the team that controls the game. The ball is the key to the game because if your team has the ball the opposing team cannot create damage to you and score goals. Also, if you have the ball the other team gets tired before because it will run after the ball chasing it down the field and will make technical errors (controls, tackles, etc ... and tactical (imbalance in defense, etc ...) that could give you the victory. finally, if you've got the ball, you decide when it's time to attack and try to score goals. in modern football, there are teams that when they have the ball, it is very difficult to take it from them, the few times they lose it is in the ending phase: shooting, dribbling, etc ...

5. Finishing. You have to shoot. The team that doesn't finish the attack must defend with speed. Once we have reached the last third of the field, we have to finish the attack and shoot for goal. The result of this action may be a goal, goal kick, a defender blocking it, the goalkeeper blocking it, corner kick, foul, etc ... If the team does not finish the attack by shooting on goal and loses the ball in an tackle or interception by defenders, then the opponent will be "kicking the ball" to counter attack.

6. Reducing and covering the free spaces where the opposing team could attack. The density favors the defense. We must teach players the concept of acting as a defensive unit, as a functional unit, all collaborating and working coordinated joining forces, movements, helping to defend. Establishing an area where to install the defensive "castle", "From here we will defend together, nothing passes through this line." Teach them how to pass to the sides of the field depending on where the ball is and how to cover spaces near the ball that could be occupied by attackers and that were created by the movements of the defenders, while watching over attackers that are far from the ball.

7. Movement of defenders in support of their teammates. You can always help a teammate in action. Basics defensive principles of marking, coverages and defensive swaps. Marking also works to cover free spaces and avoid being used by attackers. Players who could receive the ball will also be marked. Coverages occur when a defender will "attack" the attacker that has the ball and another defender gets near to "cover" his back and retrieve the ball if he gets overwhelmed by the attacker. In swaps, players who get out of their position take the defensive functions of the teammate who went out to make coverage. As we see, these basic defensive principles are closely related to how defending players move in aid from each other.

8. Recovery of the ball. As I said before: the team that has the ball is the team that controls the game. The defense will be effective if it can get the ball avoiding the goal. The technical- tactical principles related to anticipation, interception, entrance and charge. Through these actions, the defenders should win the ball.

As we have explained there are a number of principles and fundamentals in football that must be taught to players and constantly repeated for them to automate it. On offense: moving to use open spaces and support, think before receiving the ball, hold the ball and finish. In defense: reduce and fill spaces, monitor and mark attackers, move to help teammates and recover the ball.