Long pimples

If the short pimples described in 6.2 reduce sensitivity to spin without greatly altering its sign, long pimples do something more radical: they reverse it. An incoming topspin is returned as backspin; an incoming backspin comes off with forward rotation. That behaviour, disconcerting to anyone facing it for the first time, is neither a trick nor an anomaly: it is a direct consequence of the geometry of the pimple.

The physics of reversed spin

A long pimple is a slender rubber cylinder — its height matches or slightly exceeds its diameter: the rules class a pimple as long once the ratio of height to diameter passes 0.9, and do not allow it to go above 1.10 — and that proportion makes it flexible. When the ball strikes, the pimples bend sideways instead of resisting. The ball does not meet a surface offering it friction, but a set of rods that yield and go along with its rotation. As they recover their shape, the pimples push the ball in a direction that reverses the original spin.

A concrete case makes it clear. When a topspin reaches a long-pimple rubber, the ball drags the tips in its direction of rotation. The pimples tilt, absorb the rotation and, on releasing the ball, return it with a spin the opponent reads as backspin. The opposite happens with an incoming backspin: the pimples bend backwards and the restitution produces forward rotation. The spin is reversed, not cancelled.

The efficiency of the reversal depends on the geometry. Taller, thinner pimples bend more readily and produce a more marked reversal; thicker pimples within the “long” category bend less and the returned spin is weaker. The density of the grid also plays a part: more widely spaced pimples allow greater individual deflection. Those differences mean that not all long pimples behave alike, though all share the principle.

With sponge and without sponge (OX)

Long pimples are sold with or without sponge. The version without sponge — designated OX, from zero sponge — glues the topsheet directly onto the blade. Without the cushioning layer of the sponge, the ball stays in contact with the rubber for less time, the reversal of spin is more abrupt and the player perceives the blade directly. The ball comes off with less speed of its own but with a purer reversed spin, hard for the opponent to read. It is the option preferred by the classic defender who puts the opponent's discomfort ahead of the speed of the return.

With sponge — usually between 0.5 and 1.0 mm, rarely more — the contact lengthens, the ball gains some speed and the player has a minimum of attacking capacity of their own. The sponge softens the reversal and makes it less extreme, but allows more active blocks and a degree of initiative in play. Sponge thickness in long pimples is a more sensitive decision than in inverted rubbers: every tenth of a millimetre shifts the balance between defensive control and the possibility of attack.

Frictional and non-frictional pimples

Not all long pimples are alike in their surface treatment. Non-frictional pimples have a smooth, almost slippery surface that minimises adhesion between the tip of the pimple and the ball. They are the ones that produce the purest reversal of spin: the ball slides over the pimples, these bend and return a cleanly reversed spin. They are the option for the pure defender, who builds points by returning an awkward spin without aiming to generate rotation of their own.

Frictional pimples present a treated surface that adds a certain roughness to the tips. That roughness lets the player generate some spin of their own — an active chop, a block with variation — at the cost of reducing the purity of the reversal. The returned spin is less disconcerting for the opponent, but the user gains versatility: they can alternate between returning reversed spin and producing spin of their own, which widens their tactical repertoire. The ITTF, for its part, set the limit at the other extreme: since July 2008 it has required a minimum level of friction for every pimples-out rubber, which ruled out long pimples with no friction at all. Today's “non-frictional” pimples are, strictly speaking, low-friction ones.

Modern defensive play and the blocker-chopper

Long pimples are the tool of the defender and the blocker. The modern chopper — the player who combines defensive chop from a distance with occasional counter-attacks — usually carries long pimples on one side, normally the backhand, and an inverted rubber on the other. The asymmetry is deliberate: with the inverted rubber they attack and generate spin; with the pimples they return a reversed spin that forces the opponent to adjust every stroke. The constant switching of surface during exchanges is part of the weapon.

The blocker close to the table uses long pimples differently. Instead of the chop from a distance, they block from close in, absorbing the opponent's power and returning balls with a spin that does not match expectations. A block on a topspin comes off with backspin; the opponent, failing to read it, puts the ball into the net. That style of play demands less physical condition than the chop from a distance but more reading of the game and more precision in placement.

Both profiles — chopper and blocker — share a characteristic: their effectiveness depends less on their own power than on the discomfort they generate in the opponent. Long pimples do not win points through speed; they win them through confusion.

The difficulty of playing against and playing with

Long pimples are difficult in both directions. For the opponent, the difficulty is the reading. Every stroke arriving from the pimpled side carries a spin reversed from what is expected, and the adjustment has to be made in milliseconds. A player used to facing only inverted rubbers needs to recalibrate their whole system of response: the bat angles, the height of the stroke, the anticipation. Many club players lose matches against long pimples not because the defender is better, but because they cannot read what is coming at them. Section 20.6 addresses the myth that pimples are “cheating”.

For the user, the difficulty is symmetrical. Long pimples return the spin they receive; if they receive no spin, they return almost nothing. The player with pimples has to understand what rotation the incoming ball carries in order to anticipate what spin will leave their side. Against an opponent who varies their spin a great deal, pimples are a formidable weapon. Against an opponent who hits flat and without rotation, they lose much of their usefulness. Learning to play with long pimples means learning to read incoming spin more attentively than any other user of rubber.

Reference models

Butterfly's Feint Long is the classic coordinate: available in several versions ranging from the non-frictional to the moderately adherent. Stiga's Curl offers a similar profile with nuances of its own surface. Tibhar's Grass D.TecS sits at the frictional extreme, with the capacity to generate active spin. Der Materialspezialist, a niche brand, manufactures several models aimed at the pure defender. On the Chinese side, 729's 755 is a historic long pimple present in clubs all over the world.

As with short pimples, the choice of model matters less than understanding what is being sought: pure reversal and maximum discomfort, or a compromise with some attacking capacity of one's own. Section 6.6 places long pimples on the map of player profiles, and 12.5 describes the complete defensive bat in which these pimples fulfil their function.