There have been a number of critical changes to the Laws of Badminton. This document outlines and explains those changes, with critical portions highlighted in red.

Apart from the changes to the scoring system (see Rally Point System), the following major changes to the Laws of Badminton came into effect in May 2006. Most other changes were merely changes to the numbering of the Laws, or minor vocabulary changes (e.g. changing "may" to "shall").

Law 9.1.1

Previously:

In a correct service neither side shall cause undue delay to the delivery of the service once server and receiver have taken their respective positions;

Now:

In a correct service neither side shall cause undue delay to the delivery of the service once the server and the receiver are ready for the service. On completion of the backward movement of server’s racket head, any delay in the start of the service (Law 9.2), shall be considered to be an undue delay;

Notes:

1. The first part of this Law has not changed. However, in the past, it was only the umpire's job to police this Law, but now the service judge calls a service fault, with the same signal as for a double movement.
2. The second part of the Law is a new addition - a player cannot pause at the end of his/her back swing at all. Any delay at the end of the back swing must be faulted.

Law 9.1.5

Previously:

In a correct service the whole shuttle shall be below the server’s waist at the instant of being hit by the server’s racket;

Now:

In a correct service the whole shuttle shall be below the server’s waist at the instant of being hit by the server’s racket. The waist shall be considered to be an imaginary line round the body, level with the lowest part of the server’s bottom rib;

Notes:

1. The Law itself hasn't changed; only the definition of "waist" has been added.
2. Of course, it is not possible to see a player's bottom rib in order to determine the position of the waist. However, a good guide is to use the bottom of the elbow when the player is standing with his/her arms at their side. On almost every person, the bottom of the elbow lines up with the lowest part of their bottom rib.

Law 9.1.6

Previously:

In a correct service the shaft of the server’s racket at the instant of hitting the shuttle shall be pointing in a downward direction to such an extent that the whole of the head of the racket is discernibly below the whole of the server’s hand holding the racket;

Now:

In a correct service the shaft of the server’s racket at the instant of hitting the shuttle shall be pointing in a downward direction;

Notes:

1. Horizontal is a fault! The racket must be pointing downwards, even if by only a tiny margin.
2. Be aware that, if a player is "pushing the limits" of this Law, then it is highly likely that he/she is also "pushing the limits" of Law 9.1.5.

Law 12.2

Previously:

If a service court error is discovered before the next service is delivered:

if one side made the error and won the rally, it shall be a 'let';

if one side made the error and lost the rally, the error shall not be corrected;

if both sides made an error, it shall be a 'let'.

In the early drafts of the new Laws:

If a service court error is made, the error shall not be corrected and the play in that game shall proceed without changing the players’ new service courts (nor, when relevant, the new order of serving).

Now:

If a service court error is discovered, the error shall be corrected and the existing score shall stand.

Notes:

1. There are no lets any more - the existing score shall stand, regardless of who served and/or received incorrectly.
2. In the early drafts of the new Laws, any service court errors were not to be corrected. This lead to players taking advantage of the situation and "deliberately" getting themselves positioned on the wrong side, usually when receiving, so that when the serve came back to their side, they could serve again. This is no longer possible, since the error must now be corrected.
3. The score sheet is to be marked with the letter C in the column where the error was corrected.
4. Example: At 4-all in the game below, Joan Smith is meant to be serving. If John Smith actually serves (and wins), the score becomes 5-4. If, at that point, the error is discovered, Joan Smith immediately takes over the serving, with the score remaining on 5-4. The letter C is placed against John Smith's name in the column where the correction was made, as below:

Law 13.3.3

Previously (13.2.3):

It is a ‘fault’ if, in play, the shuttle fails to pass the net;

Now:

It shall be a ‘fault’ if, in play, the shuttle fails to pass over the net;

Notes:

1. A player is no longer allowed to hit a shuttle around the side of the net post!

Law 13.3.8

Previously (13.6.2):

It is a ‘fault’ if, in play, the shuttle is hit twice in succession by the same player with two strokes;

Now:

It shall be a ‘fault’ if, in play, the shuttle is hit twice in succession by the same player. However, a shuttle hitting the head and the stringed area of the racket in one stroke shall not be a ‘fault’;

Notes:

1. The original Law only disallowed the same player hitting the shuttle with two strokes. That has been dropped in the new Law, which means that a player may not hit the shuttle twice in succession even with a single stroke.
2. However, it is OK for a shuttle to hit the head and strings of a racket in one stroke, even though that may sound like a double hit.

Law 13.3.10

Previously (13.6.4):

It is a ‘fault’ if, in play, the shuttle touches a player’s racket and continues towards the back of that player’s court;

Now:

It shall be a ‘fault’ if, in play, the shuttle touches a player’s racket and does not travel towards the opponent’s court;

Notes:

1. This is a minor change, and only impacts your calling of "Fault". In the past, technically you would only call "Fault" if the shuttle tipped a players racket and continued backwards. Now, you should call "Fault" any time that the shuttle hits a players racket and doesn't travel towards the net (e.g. travels sideways).
2. One implication of this is, if you only have two sideline line judges, and they are calling the full length of the line, if a player hits the shuttle sideways out the court, and you call "Fault", it takes the responsibility away from the line judge of having to call "Out"!

Law 14.2.5

New Law:

It shall be a ‘let’, if in the opinion of the umpire, the play is disrupted or a player of the opposing side is distracted by a coach;

Notes:

1. This Law has been added to allow the umpire to control situations where a player's coach is disrupting play, given that coaches are now allowed to coach during a match, provided that the shuttle is not in play.
2. This Law would invariably be invoked if a player's coach calls out or makes some gesture during a rally.

Law 16.5.1

Previously:

Except in the intervals provided in Laws 16.2 and 16.3, no player shall be permitted to receive advice during a match.

Now:

Only when the shuttle is not in play (Law 15), a player shall be permitted to receive advice during a match.

Notes:

1. A coach, ideally sitting in a designated seat at the back of the court, can now instruct his player during a match, provided the shuttle is not in play.
2. Any such coaching should not disrupt the play - the continuous play law still applies, so umpires should watch for players taking too long to wander towards the back of the court seeking advice.