The Free-Arm Obstruction Rule in Table Tennis, Explained
The free-arm obstruction rule is part of Law 2.6, the service law. From 1 September 2002 the ITTF introduced a service rule meant to make the serve an open technique that is fully visible to the receiver at all times.
Short answer: From the start of service until the ball is struck, it must stay above the level of the playing surface and behind the server’s end line, and it must not be hidden from the receiver by the server, the doubles partner or anything they wear or carry. As soon as the ball has been projected, the server’s free arm and hand must be removed from the space between the ball and the net (ITTF Statutes 2026, Law 2.6).
Table of Contents
The Rule, Stated Precisely
The core requirement, as worded in the ITTF Statutes 2026: “From the start of service until it is struck, the ball shall be above the level of the playing surface and behind the server’s end line, and it shall not be hidden from the receiver by the server or his or her doubles partner or by anything they wear or carry.” A separate sentence covers the free arm: “As soon as the ball has been projected, the server’s free arm and hand shall be removed from the space between the ball and the net.” The Law defines that space as “defined by the ball, the net and its indefinite upward extension.”
📊 Note: The Law has three separate parts: the ball’s position (above the level of the playing surface and behind the end line), the visibility requirement (the ball must not be hidden from the receiver by the server, the doubles partner or anything they wear or carry), and the free-arm requirement (arm and hand removed from the space between the ball and the net once the ball is projected).
Why This Rule Exists
An ITTF notice about the service rule that took effect on 1 September 2002, republished by Megaspin, describes the intent as making service an “OPEN” technique that is fully visible to the receiver at all times. For servers, the notice advised swinging the free arm out of the way as fast as possible on forehand serves.
Where to Find the Rule
In the ITTF Statutes 2026 the service law is Law 2.6, in chapter 2 (The Laws of Table Tennis). The visibility requirement and the free-arm requirement are separate sentences within it.
⚠️ Watch out: If you need the exact wording for an official purpose, such as citing it to a tournament official in a dispute, use the current edition of the ITTF Statutes, because the wording is amended from time to time.
Does This Apply to the Non-Serving Doubles Partner?
Yes. The Law names the doubles partner alongside the server: the ball “shall not be hidden from the receiver by the server or his or her doubles partner or by anything they wear or carry.” So the server’s partner also has to stay out of the receiver’s view of the ball during the serve.
What Counts as a Violation in Practice
The visibility requirement runs “from the start of service until it is struck”, so it is not limited to one moment. A server who tosses legally but then moves a shoulder, the free arm or clothing in front of the ball before it is struck would be hiding the ball during that window.
The Consequence of a Violation
An incorrect service scores a point for the opponent: the Laws list “if an opponent fails to make a correct service” among the ways a player scores a point (Law 2.10), and it is not a let. There is one exception to the immediate point. If the umpire or assistant umpire is not sure about the legality of a service, they may, on the first occasion in a match, interrupt play and warn the server. After that, any service by that player or the doubles partner that is not clearly legal is considered incorrect (Law 2.6).
How This Connects to Serve Disguise, Legally
It is worth distinguishing this rule from legal serve disguise. Legal disguise, keeping your setup and early swing motion consistent regardless of the spin you’re about to impart, works entirely within the requirement that the ball stays visible to the receiver. It’s a legal way to make a serve harder to read, through motion consistency rather than physically blocking the receiver’s view. Hiding the ball from the receiver with the body, the free arm or clothing is a different matter, and it is what the Law prohibits.
💡 Pro tip: If you’re working on making your serves harder to read, invest in the legal disguise principles, consistent setup and motion, rather than experimenting with body positioning that could draw a fault under this rule. The legal route is also the more durable one, since a good motion-based disguise doesn’t rely on an umpire failing to notice an obstruction.
Who Decides Whether a Serve Is Legal
The Laws put the responsibility on the server: “It is the responsibility of the player to serve so that the umpire or the assistant umpire can be satisfied that he or she complies with the requirements of the Laws, and either may decide that a service is incorrect.” A serve the umpire cannot be satisfied is legal can therefore be called incorrect.
A Common Misunderstanding Among Newer Players
Players sometimes assume this rule only concerns keeping the body out of the way, without realizing that the free arm has its own requirement. A server might believe they comply because their torso is not hiding the ball, while the free arm and hand are still in the space between the ball and the net after the ball has been projected. Both requirements apply together.
The Rule Is Written About the Ball
The current Law text is written about the ball: the ball must not be hidden from the receiver by the server, the doubles partner or anything they wear or carry. The sentence about the free arm and hand is separate and concerns the space between the ball and the net.
What This Looks Like Compared to a Legal Serve
A legal serve under the current Law keeps the ball above the level of the playing surface and behind the end line, keeps the server, the doubles partner and anything they wear or carry from hiding the ball, and gets the free arm and hand out of the space between the ball and the net once the ball has been projected. The text of Law 2.6 does not prescribe a particular stance.
- ✓Keep the ball above the level of the playing surface and behind the end line until it is struck
- ✓Remove your free arm and hand from the space between the ball and the net as soon as the ball has been projected
- ✓Keep your body and clothing from hiding the ball from the receiver at any point before it is struck
- ✓Serve so the umpire can be satisfied that you comply with the Law
- ✕Use your body, free arm or clothing to hide the ball from the receiver
- ✕Leave your free arm or hand in the space between the ball and the net after the ball has been projected
- ✕Assume only the initial toss needs to be visible, ignoring the moment right before contact
- ✕Forget this applies to a non-serving doubles partner’s positioning too
A Practical Self-Check for Your Own Serve
If you learned to play table tennis more casually rather than through formal coaching, it’s worth deliberately checking your own service motion against this rule at least once, ideally with a training partner watching specifically for it. Ask them to confirm they can clearly see the ball throughout your toss and your racket making contact, from their actual receiving position rather than from beside the table where obstruction is much easier to miss.
The Short Version, Restated
From the start of service until the ball is struck, it must not be hidden from the receiver by the server, the doubles partner or anything they wear or carry, and the free arm and hand must leave the space between the ball and the net as soon as the ball has been projected. An incorrect service scores a point for the receiver, subject to the umpire’s option to warn on the first doubtful serve in a match.
Common Questions
What is the free-arm obstruction rule in table tennis?
From the start of service until the ball is struck, it must not be hidden from the receiver by the server, the doubles partner or anything they wear or carry, and the server’s free arm and hand must be removed from the space between the ball and the net as soon as the ball has been projected.
Why was this rule introduced?
An ITTF notice for the service rule that took effect on 1 September 2002 describes the aim as making service an open technique that is fully visible to the receiver at all times.
What happens if a server violates this rule?
An incorrect service scores a point for the receiver and is not a let. If the umpire is unsure on the first occasion in a match, they may interrupt play and warn the server instead.
Does this rule apply to a doubles partner too?
Yes, the Law names the server’s doubles partner alongside the server: the ball must not be hidden from the receiver by either of them or by anything they wear or carry.
Is only the initial ball toss covered by this rule?
No, the entire window from toss to contact must stay visible, not just the moment of the toss itself.
The Short Version
- →The ball must not be hidden from the receiver from the start of service until it is struck.
- →The free arm and hand must leave the space between the ball and the net as soon as the ball is projected.
- →An ITTF service rule change took effect on 1 September 2002 to make the serve visible to the receiver.
- →An incorrect service scores a point for the receiver, not a let, apart from the umpire’s option to warn on the first doubtful serve.
- →The rule explicitly covers a doubles partner’s positioning too.
- →For official purposes, quote the wording in the current edition of the ITTF Statutes.
Benjamin Fink is the Lead Equipment Analyst and Senior Contributor at Ping Pong Reviewed. A competitive USATT tournament player and table tennis technician with over 12 years of testing experience, Benjamin specializes in blade carbon composite physics, rubber sponge durometer hardness testing, ITTF equipment compliance, and table tennis robotics mechanics.
