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Badminton — BWF Law 17 and ITTO Sections 2, 5, 7 and 8

Each badminton official decides a different part of the match.

The Referee controls the tournament, the Umpire controls the match and court, the service judge watches the server's delivery, and line judges decide whether the shuttle landed in or out on their assigned lines. Their calls and signals fit together; they are not four officials giving opinions on the same incident.

Quick ruling: under the Badminton World Federation Laws of Badminton and Instructions to Technical Officials effective 1 July 2026, an official's factual decision is final within that official's responsibility. The main exceptions are a clearly wrong line call that the Umpire is certain is incorrect and a line call decided through the Instant Review System where it is in use.
Officials at a glance

Who is responsible for what?

  • Referee: has overall authority for the tournament or championship. The Referee appoints the Umpire for a match and remains the final authority on unresolved questions about interpreting the Laws.
  • Umpire: is in charge of the match, court, and immediate surroundings. The Umpire enforces the Laws, calls faults and lets, announces the score, handles appeals, manages the other on-court officials, and reports to the Referee.
  • Service judge: decides whether the server complies with BWF Laws 9.1.2 through 9.1.8. The service judge calls a service fault and uses the approved signal identifying the broken service requirement.
  • Line judge: decides in or out for the line or lines assigned to that position. The line judge does not decide net faults, player contact, service order, or the score.

This division comes from BWF Law 17 and ITTO Section 2, both effective 1 July 2026. A tournament can operate with fewer on-court officials, but responsibility for any missing duty must still be allocated.

Referee versus Umpire

The Referee does not normally call each rally

In BWF terminology, the Referee runs the event while the Umpire sits in the chair and controls an individual match. The Umpire decides ordinary match questions without asking the Referee to confirm every ruling.

The Referee becomes involved when called to court, when an unresolved appeal concerns interpretation of the Laws, when a tournament-level decision is required, or when the Umpire reports serious misconduct. An appeal about what physically happened is not converted into a question of law merely because a player disagrees with the on-court official.

Umpire control

The Umpire combines decisions, announcements, and match management

BWF Law 17.6 requires the Umpire to enforce the Laws, call a fault or let when appropriate, decide timely appeals, keep players and spectators informed, arrange unfilled officiating duties, record misconduct, and refer unresolved questions of law to the Referee.

The Umpire also confirms the score and which side serves. The score is always announced with the serving side's score first. “Service over” means that the right to serve has changed; it is not a separate penalty or an extra point.

Umpire signals

Most Umpire rulings are spoken, not mimed

The BWF ITTO effective 1 July 2026 relies on standard vocabulary such as “Play,” “Fault,” “Let,” “Service over,” the score, and specific correction or review announcements. There is no general catalogue of Umpire gestures that substitutes for these spoken calls.

  • Right hand raised above the head: the Umpire is calling the Referee to the court.
  • Left hand raised above the head: in the Instant Review System procedure, the Umpire is requesting or administering review of a line call.
  • Pointing right or left: the Umpire identifies the players or sides during the match introduction where required.
  • Yellow, red, or black card held above the head in the right hand: the Umpire is communicating a misconduct warning, misconduct fault, or Referee-ordered disqualification. The card procedure is explained in the badminton misconduct and penalty-card guide.

A player should follow the Umpire's announcement and the resulting score rather than infer a ruling from a single movement viewed out of context.

Fault and let calls

Silence does not always mean that no decision was made

The Umpire normally announces “Fault” when a fault occurs. The 2026 BWF ITTO allows the announcement to be omitted for certain obvious faults and when a line judge's out call and signal already communicate the decision. The Umpire may still explain the ruling when players or spectators need clarification.

“Let” stops and replays play since the last service: the previous server serves again and the intervening rally does not count. It is used only when a BWF Law creates a let, including the narrow case where an assigned line judge is unsighted and neither the Umpire nor the available review system can decide the landing.

Service judge

A service judge watches the server, not every service dispute

Under BWF Law 17.3 effective 1 July 2026, the service judge calls faults committed by the server under Laws 9.1.2 through 9.1.8. These include undue delay after the backswing is complete; service-court or stationary-foot violations; failing to strike the shuttle's base first or adding spin; striking above the applicable height limit; failing to continue the racket's forward movement; and missing the shuttle while attempting to serve.

The service judge calls “Fault” loudly and uses the official BWF hand signal for the specific violation. The Umpire then confirms that the fault is against the server and uses the standard vocabulary to identify the reason. The diagrams in ITTO Section 7 are the controlling visual reference; an informal gesture learned at a club does not replace them.

The Umpire still watches the receiver and may also call a service fault. The service judge may additionally manage shuttle changes and perform other tasks assigned by the Umpire, such as checking the net or an uncovered sideline.

Line judge — out

“Out” is both a voice call and a two-arm signal

When the shuttle lands outside an assigned boundary, BWF ITTO 8.3 effective 1 July 2026 instructs the line judge to call “Out” promptly and clearly, extend both arms horizontally to the sides, and look toward the Umpire. The signal is required even when the shuttle is a long way outside the line.

The landing must be judged against the boundary active for that rally. A shuttle touching the applicable line is in under BWF Law 1.3. Singles, doubles, and service can use different boundaries; the in-or-out and line-call guide explains those choices in detail.

Line judge — in

An in signal is deliberately silent

For an in landing, the line judge says nothing, points to the line with the right hand, and looks at the Umpire. That silence is the prescribed BWF procedure when paired with the pointing signal; it is not indecision.

The line judge must wait until the shuttle touches the floor or something outside the court before calling. A bounce or slide after impact does not change the landing point.

Line judge — unsighted

Both hands over the eyes means no view

If the line judge could not see the landing, BWF ITTO 8.5 requires both hands to cover the eyes immediately. This is an unsighted signal, not an in call and not a request to guess.

The Umpire then decides if able. If the Umpire is also unable to decide and no Instant Review System supplies a decision, BWF Laws 14.2.6 and 17.6.6 require a let. Where review is operating, the Umpire announces that the call was not seen, raises the left hand, and asks the system for a decision.

Earlier faults

A line judge reports the landing even if another fault appears obvious

BWF ITTO 8.7 effective 1 July 2026 instructs line judges to make their assigned call without waiting for the Umpire's ruling on another fault. For example, a line judge still reports the landing even if the shuttle appeared to touch a player, clothing, or racket first.

This preserves each official's evidence. The Umpire then decides the full sequence and applies the earliest decisive event under the Laws; the line judge does not abandon an assigned factual observation to decide a different kind of fault.

Overruling

A close call is not enough reason to overrule a line judge

BWF Law 17.5.1 sets a high threshold: the Umpire overrules when it is beyond reasonable doubt that the line judge clearly made the wrong call. The Umpire then immediately announces “Correction, IN” or “Correction, OUT.” The replacement call becomes the match decision.

This power is an exception to the usual rule that the official assigned to a factual question makes the final decision. It is not a licence for the Umpire to reconsider every close landing or to prefer a player's view.

Instant review

Video review replaces the original line decision where available

When the BWF Instant Review System is operating, a player must say “Challenge” and/or clearly raise a hand immediately after observing the line decision. The Umpire verifies that the player has a valid challenge, announces it, and raises the left hand while the system reviews the call.

An IN or OUT system result controls the landing. If the system returns “No Decision,” an existing seen call remains in force; an original unsighted call becomes a let. Review availability and the number of unsuccessful challenges allowed are competition procedures, not changes to the underlying boundary rule.

Appeals

Facts and interpretations follow different routes

Under BWF Law 17.6.2 effective 1 July 2026, a player must raise a disputed point before the next service is delivered. The Umpire decides the appeal. If the player remains dissatisfied, only an unresolved question about interpreting the Laws is referred to the Referee.

  • Fact: “The shuttle landed outside.” The assigned line-call process decides this, subject to the stated overrule and review exceptions.
  • Interpretation: “The wrong rear boundary was used for this doubles serve.” This concerns which Law applies and may be referred to the Referee if unresolved.
  • At match end: an appeal must be made before the appealing side leaves the court.

A player may ask for clarification, but cannot require the Umpire to consult spectators, coaches, or an unofficial recording. BWF ITTO 6.9 specifically tells Umpires not to ask or be influenced by spectators.

Reduced crews

Not every match has the full international officiating team

BWF Law 17 allows the Umpire to arrange for unfilled duties to be performed. With no appointed line judge, the Umpire makes the line decision. The 2026 BWF ITTO also permits the service judge to cover a nearby sideline after players are informed.

A recreational or school match with no appointed Umpire does not suddenly acquire the full BWF chair-umpire signal procedure. The organiser's rules should identify who calls lines and resolves disputes. Any local procedure allocates responsibility; it should not be presented as a universal BWF officiating rule.

Common mistakes

Misunderstandings to avoid

  • “The Referee sits in the chair.” In BWF terminology, that match official is the Umpire; the Referee controls the tournament.
  • “A silent line judge called nothing.” An in landing is communicated silently by pointing at the line.
  • “Both hands over the eyes means in.” It means the line judge was unsighted.
  • “The Umpire can freely change a close line call.” BWF Law 17.5.1 requires a clearly wrong call beyond reasonable doubt.
  • “Any disagreement is a let.” A seen factual call remains a decision; the unsighted let applies only when the authorised decision-makers cannot decide.
  • “A service judge decides whether the serve landed in.” The service judge judges the server's delivery; the assigned line judge or Umpire decides the landing.
  • “Every Umpire decision has a hand signal.” BWF procedure is primarily verbal, with particular gestures for defined situations.
Effective rulesets

Version check

This page applies the Badminton World Federation Laws of Badminton, BWF Statutes Section 4.1, effective 1 July 2026, especially Laws 1.3, 9, 14.2.6, 16.7, and 17. It uses the BWF Instructions to Technical Officials, Section 4.1.1, effective 1 July 2026, especially Sections 2, 5.3–5.8, 5.17, and 6–8, for official duties, vocabulary, Umpire gestures, review administration, service-judge signals, and line-judge signals. Instant Review System availability and local officiating arrangements must be checked in the regulations governing the competition.