The scoring system in badminton

Deciding who gets to serve first

In a major tournament, a coin toss is used to decide which side will serve first.
In more casual club or league games, you usually just throw the shuttle up in the air, let it land, and see which side it points towards: that side serves first.

Points, games, and matches

Every time you win a rally, you get a point. Starting from zero, the first person to reach 21 points wins the game. In club badminton, this is usually where you stop and choose players for the next game.
In standard league or tournament play, however, what really matters is the match. A match is the best of three games: you win the match by winning two games. So a match could last either two or three games.
Whenever you win a rally, you also get the next serve. So if your opponent was serving in the last rally, the serve passes to you; if you were serving, you keep on serving.

To win, you need a two-point lead

You have to win the game by at least two points. If the score reaches 20–20, then 21 points are no longer enough to win the game. You need to win two clear points: two points in a row, one after the other.
For example, 22–20 would be a winning score, as would 25–23. But 21–20 would not be enough, and neither would 24–23.
If you reach 30–29, however, you’ve won the game. 30 points is the upper limit. This rule is intended to prevent games dragging on too long, especially at the top level of play, where excessively long games put athletes at risk of injury.

Always say the server’s score first

It’s a good habit to say the score to your opponent before starting each rally. It’s surprisingly easy to lose track of the score, and saying it between rallies helps prevent disputes.
When you’re saying the score, always say the server’s score first. So if you are serving and have 10 points to your opponent’s 15 points, then the score is 10–15 (not 15–10).

Which side to serve from?

Remember that you have two service courts: one on the right, and one on the left.
When the server’s score is an even number, he serves from the right service court. When his score is an odd number, he serves from the left service court. For this reason, the right service court is also known as the even service court, and the left service court is known as the odd service court.

Odd numbers? Even numbers?

• Odd numbers start at 1, and go up by 2
• Even numbers start at 0, and go up by 2

So the odd numbers are 1, 3, 5, 7, 9, 11, 13, and so on. The even numbers are 0, 2, 4, 6, 8, 10, 12, and so on.
Even and odd numbers alternate. So if you keep winning rallies, you’ll keep serving from a different side each time: right, left, right, left, right, and so on.
Because zero is an even number, the game always starts with someone serving from the right (even) service court.

What about the receiver?

The receiver’s position is determined not by his own score, but by the server’s score. The receiver always stands in the service box diagonally opposite from the server. In other words, both players will be in the even service courts, or both will be in the odd service courts. You can never have one of each (one odd, one even).

Scoring in doubles

The actual scoring in doubles is simple: instead of each person winning points, each pair wins points. The part that often confuses people is this: how do you decide who serves, who receives, and which side they should be on?
At the start of the game, when the score is 0–0, the serving pair choose who serves for the first rally, and the receiving pair choose who receives.
The even/odd rule still holds. So if the server’s score is odd, he will serve from the left court (if even, from the right). Just as for singles, the receiver will stand in the diagonally opposite service court.
Whenever the serving side wins a rally, the same person serves again (but from the other service court). The serve does not alternate between the partners: it stays with one person, until the opponents win a rally and get the serve.

Everyone has a service court

To make sense of doubles scoring, you must understand two crucial ideas:

• Every player has a service court, at all times.
• When your partner has one service court, you have the other one.

Let’s take an example: you are getting ready to serve from your left service court. So your service court is obvious: it’s the box you have to stand inside.
Your partner is not serving or receiving, so he doesn’t have to stay within one of the service boxes: he can stand anywhere on your court. Nevertheless, we say that your partner has the right service court.
Bizarrely, most people say that your partner is in the right service court. This makes no sense at all, because your partner probably has one foot in each service court!
The same idea applies to the receiving side. In this example, the receiver has the left service court, and his partner has the right service court. Until you serve, the receiver must stay within his service court, but the receiver’s partner can stand wherever he wants.

It doesn’t matter where you go during the rally

Suppose you serve from the right service court. By the end of the rally, you could easily be standing inside the left service box with your partner standing inside the right box. This has no effect on your service courts for the next rally.
In other words, the service courts are set at the start of the rally. Although you move around during the rally, the service courts don’t change. At the end of the rally, you have to remember what your service courts were:

• Who was serving?
• Who was receiving?
• From which side?

Once you remember this, you work out the positions for the next rally.

When you serve and win the rally

Suppose you serve, and then your side wins the rally. For the next rally, you will serve again, but from the other side. In other words:
When the serving side win a rally, the server and his partner swap service courts.
Remember that you and your partner must always have different service courts. That’s why the server’s partner also changes service court here. This change has no effect on the server’s partner — he can still stand wherever he wants — but he needs to remember his service court for future rallies.
The receivers never change their service courts. The only way to change service courts is to win a point when your side is serving.

When the receivers win a rally

When the receiving side wins a rally, the serve passes to them. Their service courts do not change from the previous rally.
If their new score is odd, then whoever has the left service court will serve; if the score is even, then whoever has the right service court will serve.

Consequences of this system

If you think it through carefully, you can figure out two interesting consequences of this system:

• You never serve to the same person in two consecutive rallies.
• When you win back the serve, the new server is whoever wasn’t serving last time.

The rules actually state these consequences explicitly:

11.4 Sequence of serving

In any game, the right to serve shall pass consecutively:

11.4.1

from the initial server who started the game from the right service court

11.4.2

to the partner of the initial receiver

11.4.3

to the partner of the initial server

11.4.4

to the initial receiver

11.4.5

to the initial server, and so on.

11.5

No player shall serve or receive out of turn, or receive two consecutive services in the same game, except as provided in Law 12.

(Law 12 is about how you correct mistakes. We’ll look at that later.)
It’s easy to forget the score or forget which side you were on. When you forget, you can usually use those two facts to help remember.
For example, suppose you have just won back the serve. You know the score is 10–8, but you cannot remember which side you should be. You also know that last time, your partner was serving (not you). Therefore, you must be serving from the right service court.
Source--badmintonbibl