When the referee starts waving his arms about after blowing the whistle, do you know what he is indicating?
He may be conducting himself in a medieval dance, but more likely he will be signalling a free-kick.
Here is our guide to the referee's signals.
The referee should point with a raised arm in the direction that the free-kick has been given.
The referee does need to make a further signal to indicate it is direct.
Players often wait before taking a free-kick to check with the ref whether it is direct or indirect.
The referee will signal the positioning and direction of an indirect free-kick in the same way as any other free-kick.
However, to show that the kick is indirect the referee keeps one arm outstretched above his head until after the kick is taken.
It avoids any confusion when a goal is scored directly from a free-kick.
These are not the signals you should be wanting a ref to show you.
The signal for a caution or sending off is the same - it's just the colour of the card that is different.
The referee will take a note of the player and then hold the card high above the head with an outstretched arm.
If the player is sent off for two bookable offences, the referee will show the second yellow card before holding up the red card.
It is possible, though, that a player who has already been booked can be shown a straight red card.
(Read "When is a Card Yellow or Red?")
Even after a foul, a ref may allow play to continue sometimes.
He will look to see if the team that would have been awarded the free-kick has an advantage in playing on.
To signal that he is waving play on, he will extend both arms out in front of his body.
Know Your Assistant Referee's Signals
That person on the touchline might look as though he's waving in some low flying aircraft but those flags have a very important role.
They used to be called linesmen but now they're referee assistants and they help the referee with offside decisions and signal a number of things, such as throw-ins and substitutions.
So what are these signals?
Well you don't need a degree in semaphore to understand what they all mean.
Here is our guide to the referee assistant signals.
When the whole of the ball crosses the line, it's time for a throw-in.
The assistant referee will hold up the flag in the direction that the team which is awarded the throw-in is attacking.
The assistant will stand at the point where the ball crossed the line.
But only if the ball goes out in the half of the pitch he is marshalling.
If the manager decides it's time to change the team then this is the signal you'll see on the touchline.
The arms go up in the air and holding on to both sides of the flag, it is hung above the head of the referee's assistant.
Not the sort of signal you want to see if 30 seconds before you've just blazed a penalty over the bar.
There are three different signals for an offside.
But the type of signal is dependent on where the offside offence is committed.
The position where the assistant holds his flag makes it clear to the referee, players and spectators which player is being penalised for offside.
From the graphic above, here are the three scenarios:
1. FAR SIDE
The first signal is for offsides on the far side of the pitch. The assistant referee will hold the flag out in front of him at above head height.
The second signal indicates that a player in the centre of the pitch has strayed offside. The flag will be held out with an outstretched arm at shoulder height.
3. NEAR SIDE
If a player on the side of the pitch nearest to the assistant is deemed to be offside then the flag is pointed down towards the ground in front of the body.
When is a Direct Free-kick Awarded?
When a ref blows the whistle for a foul or misconduct, it helps the kicker to know if they can kick shoot at goal.
So when is a free-kick direct or indirect?
Here are 10 offences that can lead to a direct free-kick.
When a player:
1.Kicks or attempts to kick an opponent
2.Trips or attempts to trip an opponent
3.Jumps at an opponent
4.Charges an opponent
5.Strikes or attempts to strike an opponent
6.Pushes an opponent
7.Makes contact with the opponent before touching the ball when tackling
8.Holds an opponent
9.Spits at an opponent
10.Handles the ball deliberately
If any of these offences are committed by a player inside their own penalty area then it's a penalty.
Did you know that if a team kicks a direct or indirect free-kick directly into its own goal, then a corner is awarded to the opposition?
When is a Free-kick Indirect?
With an indirect free-kick, you obviously have to pass before you can shoot.
But when are these free-kicks awarded?
When, in the opinion of the ref, a player:
1.Impedes the progression of an opponent (obstruction)
2.Plays in a dangerous manner
3.Prevents the goalkeeper from releasing the ball from his hands
4.Or when a keeper, inside their own penalty area:
5.Holds on to the ball for more than six seconds
6.Handles a back pass
7.Handles the ball after receiving it from a team-mate direct from a throw-in
8.Touches the ball again with their hands, before it is touched by another player, after releasing it from their possession
Any tackle in the penalty box is risky and when that whistle blows it's heart-sinking time.
So what is a penalty?
It's the result of any foul which would normally lead to a direct free-kick that is committed by a team inside their own penalty area.
The player gets a shot at goal from 12 yards out.
The rules of a penalty are that:
1.The goalkeeper can move sideways before the kick is taken but must stay on his goal line
2.All the other players must stand outside the penalty box and cannot enter the area until the ball has been kicked
3.The kicker cannot touch the ball a second time until it has been touched by another player
4.If the referee spots a team-mate of the kicker entering the area before the kick is taken, he can a) order the penalty to be retaken if the penalty is scored, or b) if the penalty is missed, the defending team get an indirect free-kick
5.If a defender moves into the area and the penalty is missed then the penalty is again retaken
Like most things in football, the offside rule is pretty simple - but sometimes a disallowed goal will open up the grey areas ever so often.
An amendment to the rule was introduced at the start of the 2003/04 season, which allows a player to be in an offside position provided he or she is not "actively involved in play".
It was designed to promote attacking football, but different interpretations of what constitutes "active play" have led some to suggest it is open to abuse.
Fifa, world football's governing body, has clarified when a player is to be regarded as "actively involved in play":
"Interfering with play means playing or touching the ball passed or touched by a team-mate."
The changes apply to all levels of football and top strikers often exploit this by standing in an offside position as a free-kick is about to be taken.
They take advantage of the rule that, if the ball doesn't come to him, then he is not "active" and therefore onside.
However, a player doesn't necessarily have to touch the ball to influence the play. They are still offside if they are judged to be:
Got your head around the new rules? Here's our guide to the basics.
A player is in an offside position if, when the ball is played by a team-mate, they are nearer to the opposition's goal line than both the ball and the second last opponent.
Clear so far? There are a few more things to remember.
You can't be offside if:
You receive the ball directly from a goal kick, a throw-in or a corner
You are in your own half of the pitch
For any offside offence, the referee awards an indirect free-kick to the opposing team, to be taken from the place where the infringement occurred.
The different fouls that make the ref get out the red or yellow card.
There are seven different offences that can get you a yellow card:
1. Anything that can be deemed as unsporting behaviour
2. Dissent by word or action
3. Persistent infringement of the laws, for example, a series of fouls
4. Delaying the restart of play
5. Not retreating the required distance at a free-kick or corner
6. Entering or re-entering the pitch without the referee's permission
7. Deliberately leaving the pitch without the referee's permission
A player is sent off and shown the red card if they commit any of the following seven offences.
1. Serious foul play
2. Violent conduct, such as throwing a punch
3. Spitting at an opponent or another person
4. A player other than the goalkeeper denying an obvious goalscoring opportunity by deliberately handling the ball
5. Denying an obvious goalscoring opportunity to an opponent moving towards the player's goal by an offence punishable by a free-kick or a penalty kick
6. Using offensive or insulting or abusive language and/or gestures
7. Receiving a second caution in the match
"Hand to ball or ball to hand?" Nothing stirs the passion like a controversial handball decision.
You've only got to look at players and managers jumping up and down enraged at a dodgy penalty to know that.
A ball slams into a player's arm and one team is screaming for a penalty, while the others are claiming it was an accident.
It's a tricky one for the referee to call in the heat of the moment.
So what is 'deliberate' handball?
"The challenging decisions are if the defending player spreads their arms to make themselves bigger"
Former Premier League referee David Elleray
In Fifa's Laws of the Game 2005, Law 12 says a free-kick or penalty will be awarded if a player "handles the ball deliberately (except for the goalkeeper within his own penalty area)".
Page 67 of the document gives "additional information for referees, assistant referees and fourth officials".
It adds: "Referees are reminded that deliberately handling the ball is normally punished only by a direct free-kick or penalty kick if the offence occurred inside the penalty area.
"A caution or dismissal is not normally required."
However, the document fails to describe what constitutes deliberate handball, which places the responsibility firmly on the referee and referees' assistants.
Former Premier League referee David Elleray said the referee's interpretation depends on whether the hand or arm is in an "unnatural" position at the point of contact.
"Referees look at two specifics - did the hand or arm go towards the ball or in a manner which would block the ball, or is the hand in a position where it would not normally be?" Elleray told BBC Sport.
"The challenging decisions are if the defending player spreads their arms to make themselves bigger.
"If the ball hits the arm then the referee must decide whether this action was to deliberately block the ball or whether the player has raised their arms to protect themselves - especially if the ball is hit at speed."
The referee and referees' assistants, therefore, have a matter of seconds to weigh up these factors, and take the appropriate action.
And there will always be at least one manager, 11 players and thousands of fans who will insist they have been hard done
Did you know that not all pitches are the same size?
The length of a pitch must be between 90 m (100 yards) and 120 m (130 yards) and the width not less than 45 m (50 yards) and not more than 90m (100 yards).
And what about where most of the action happens - the penalty box?
It is also known as the 18-yard-box, with the smaller area - marked out inside it - called the six-yard-box.
This is where some of the world's best strikers earn their living.
And for all you penalty takers - or savers - out there, the most famous spot in football sits 11m (12 yards) from goal.
Last, but not least, that wooden thing at each end of the pitch they call the goal.
Think you know how big it is? It's 2.44m (eight feet high) and 7.32m (eight yards wide).