Learn the pendulum serve: legal ball toss (at least 16 cm), pendulum motion towards the body and short placement. With milestones and typical mistakes.
The honest answer: in the pendulum serve you move the racket towards your body at the moment of contact – this is how English federation coaches define the "pendulum service" [1]. It is regarded as the classic beginner serve (experience value) because you play it with the forehand, can create backspin and sidespin, and the serve belongs to you: it is the only ball your opponent does not dictate.
Before it is about spin, something unspectacular but decisive comes first: the rulebook. A serve is only valid if the ball rests freely on the open palm of your free hand, is tossed near vertically and without spin at least 16 cm, stays above table height and behind the end line, and is visible to the opponent [2]. 16 cm is about the length of a ballpoint pen.
How hard is it? The movement is learned quickly, but the clean, legal serve with control over length and spin takes longer. Plan on several training sessions (experience value). To put placement in context: in an analysis of 48 top players, the men placed 30.1 % of their serves close to the net, the women 10.9 % [3].
Place the ball on the open palm of your free hand and hold it still. Then toss it near vertically upward, without giving it spin, at least 16 cm [2]. For the start, 20 to 30 cm is good, it gives you time to aim (practice). The ball must stay free on its way up and down until you hit it.
From toss to contact, the ball stays above table height and behind the end line [2]. Your body, arm or clothing must not hide it from the opponent. As soon as the ball flies up, you remove your free arm and free hand from the space between ball and net [2].
Start with the racket beside your body. When the ball falls, swing the racket towards your body [1]. Hit the ball while it is falling [2]. The lower you brush under the ball, the more backspin it gets. The more you hit it from the side, the more sidespin (practice). The wrist delivers the speed, not the whole arm.
The ball must first touch your half of the table and then the opponent's [2]. For the short serve, the first bounce should be close to the net and the second one close to the net as well, so that on a longer path the ball could bounce a second time (practice). That takes away the opponent's attack.
Ten legal serves in a row: toss at least 16 cm, palm flat, ball visible. Then 8 out of 10 serves into the opponent's forehand half, then 7 out of 10 short into the front half. If you manage that, move on to the block. These numbers are practice standards.
Table tennis is considered low-risk, but repeating serves over and over loads shoulder, elbow and wrist. Tendon sheath inflammation, strains and sprains are among the most common findings [4]. The evidence is thin. Take breaks, warm up shoulder and wrist, and never serve more than a bucket in a row when your arm burns (experience value). This guide explains and motivates, it does not replace supervised training.
Make your movement unreadable. Good players try to read your serve before the hit: in a brain-scan study, 29 experts and 34 novices had to predict the flight path from serve videos cut at the moment of ball contact. An analysis method could tell the two groups apart from their brain activity with 90.48 % accuracy [5]. Your trick: always start with the same movement and change the contact point only at the last moment. That way it is harder for your opponent to read the spin beforehand (practice, not part of the study).
At least 16 cm, tossed near vertically and without spin, after leaving the palm. Then it has to fall without touching anything before you hit it [2]. A little higher is safer for beginners, because you get more time to hit the falling ball. For comparison: a ballpoint pen is about 15 cm long, so the minimum height is just above that.
A serve in which the racket moves towards the body at the moment of contact [1]. It is usually played with the forehand, can be short or long and can get backspin, sidespin or no spin at all. The movement is the same, only the contact point on the ball and the blade angle change (practice).
No. The ball must be visible to the opponent from toss to hit and must not be hidden by body, arm or clothing [2]. If a serve is not clearly legal, the umpire may warn you the first time. Every further unclear serve counts as a fault [2].
The English federation coaches name pendulum (movement towards the body), reverse (away from the body), kicker (heavy topspin or sidespin topspin) and float (without spin) [1]. For a start, pendulum and float are enough. Everything else, such as reverse serves or kickers, comes once your pendulum is legal and controlled.
The Block in Table Tennis: Returning Topspin Safely