Ins and Outs

In the last post, I suggested that game play is constrained by four kinds of limitation: explicit rules, implicit rules, background rules, and physical limitations. Here I’ll explore the different sorts of rules, and how they interact, in the context of line calling in tennis and in table tennis.

In tennis, one of the key constraints on play is that a valid shot must take its first bounce inside the court on the opponent’s side. The difference between a brilliant winning shot and a loser can be a matter of a millimeter. At Wimbledon, there are as many as ten “line umpires”, each of whom is responsible for making the in-or-out call on a single line. The match as a whole is under the care of a chair umpire, who has the power to overrule the calls of the line umpires.

If eleven officials were needed to adjudicate line calls in every tennis game very little tennis would be played. In fact, most of the world’s tennis is played with no officials at all, and the players themselves are responsible for calling the ball in and out, and for enforcing the other rules of the game.

Tennis players need to know the rules, then, and they also need to embrace a certain dual role in the game. As competitors, they’re expected to try their best to win, and to forgo no honest opportunity to do that. But as judges of the rules, they’re expected to be even-handed, favoring their own interest no more than that of their opponent. Internalizing this separate, neutral role is central to tennis sportsmanship – an important background rule that’s essential to the operation of the sport’s explicit rules.

Making line calls is difficult, and often fraught. If an impartial line umpire, whose entire attention is focused on a single line, is fallible enough that line calls need sometimes to be overruled by the chair umpire, it’s only to be expected that there will be an appreciable error rate when they’re made by a sweaty, exhausted player, in the heat of the moment, on a point that they badly need to win.

For most players, tennis sportsmanship is understood to mean that their line calls should resolve any real uncertainty in favor of the opponent. If you know that the ball is out, you call it out. But if you’re unsure, you play on.

Not everyone subscribes to this particular background rule, however – some players are comfortable resolving a doubtful call in their own favor. But tennis players quickly acquire an bad reputation if they seem to be shading line calls to their own advantage. Suspicions of this kind undermine the game itself. The whole messy business of line calling may be a factor in the decision of some players to stop playing competitive matches, or to drop out of the sport all together.

In the late 20th century, some elite players (most notoriously John McEnroe) became famous (or infamous) for disputing line calls. For some this was simply poor sportsmanship, but it could also be considered a kind of gamesmanship. It was (mostly) tolerated, if not condoned, by tennis authorities, perhaps because it added another theatrical element to the game.

Now, at the highest level, on some courts there is also a computerized Hawk-eye system with as many as ten high speed cameras linked to a computer. Hawk-eye can be used to second-guess the calls of the humans. Each player is given a certain number of challenges against adverse decisions, and the deciding when to use the challenges has become an additional layer of strategy in the game.

Some commentators initially thought that Hawk-eye was a blemish on the game – that it interrupted the flow of play too much. But the makers of the system cleverly found a way to turn this potential distraction into a new theatrical element for the benefit of spectators. The decision of the computer system is not simply signaled with a red or a green light – it is revealed by a dramatic short video, which pictures the flight of the ball, and then zooms in on a virtual ball mark which shows where the ball landed.

In sum, line calls in tennis are a problem that tennis has addressed with limited success. Now consider the analogous problem in table tennis.

In table tennis, line umpires are unknown. That’s because the equipment itself obviates the need. A ball is in if it hits the table, and out if it doesn’t. At the highest level, there are two officials, an umpire and an assistant umpire, whose duties include making the call when there’s doubt about whether or not a ball just barely nicks the edge of the table. But this is rarely a difficult decision – except for the very thinnest of edge hits, there will be a clearly observable deflection of the ball, and a clearly audible sound.

As with tennis, most of the world’s table tennis is played with no officials at all. And, while serious table tennis involves some rather recondite rules of disputable application, No one worries much about line calls. Problems with line calls simply do not hinder anyone’s enjoyment of the game to the extent they do in tennis.

In table tennis, the equipment – the table itself – makes most in-or-out decisions self-executing. The fact of the table, then, implies a simple, objective method of determining a crucial aspect of whether a shot is allowed or not. It is, in my parlance, an implicit rule.

Despite a distinct family resemblance, tennis and table tennis are quite different sports. It would be foolish (or at least hotly disputed) to claim that one is better than the other. But it seems clear to me that, in the particular item of how the two sports deal with in-or-out calls, table tennis is much the better game.

Implicit rules rule!