Balkline Billiards Explained: 47/2, 71/2 and the Cadre

Long before three-cushion became the headline carom game, one discipline did more than any other to shape modern billiards by solving a single problem: players who could score almost forever without the balls ever leaving a corner. That discipline is balkline — known as le cadre in France, cuadro in Spain and kader in the Netherlands and Germany. Its odd-looking names — 47/2, 71/2, 47/1 — hide a simple, elegant rule. This guide decodes them.

What balkline is

Balkline is a carom game played on the same pocketless table as three-cushion, with two cue balls and one red. As in every carom game you score a point — a carom — by driving your cue ball into both other balls on a single stroke. What makes balkline different is the set of lines drawn on the cloth, parallel to the cushions, that divide the surface into rectangular regions called balk spaces. Inside any one of those regions your scoring is restricted: you may make only a set number of caroms before you are forced to drive at least one ball out.

Reading the numbers: 47/2, 71/2, 47/1

The two numbers tell you everything about the game. The first number is how far the lines sit from the cushions, in centimetres; the second is how many caroms you may score while both object balls are inside one balk space. So:

At 47 cm the lines cut the table into three columns across its width; push them out to 71 cm and only two columns fit, giving bigger, more forgiving spaces. The American cousin, 18.2 balkline, simply measures its lines in inches (18 in is about 46 cm) with a two-carom limit — almost the same game as 47/2.

The balk-space rule, in practice

Picture both object balls sitting together inside one rectangle in a game of 47/2. You may score one carom with them there, and a second — but to score a third in that same space you must first send at least one of the balls across a line and out of the rectangle. Drive a ball out and bring it back and the count resets. The whole point is that you cannot simply park the balls in one spot and grind out points; you are forced to keep moving them, which makes the game a test of control rather than of one repeated stroke.

Anchor spaces: closing the loophole

Clever players soon found a gap in the rule. If they balanced the two balls right on a balkline against a cushion, the balls technically sat in two different spaces — so the restriction did not apply and the endless scoring returned. The fix, introduced by the Chicago billiard-hall owner J. E. Parker in 1894, was the anchor space (the ancre, nicknamed Parker's box): a small rectangle straddling the point where each balkline meets the rail, roughly 18 cm across, inside which both balls count as in balk no matter which side of the line they fall. The anchor closed the loophole and is still marked on every balkline table today.

Why balkline exists: the war on nursing

Balkline was a deliberate answer to its predecessor, straight rail (free carom). In straight rail there are no restricted zones at all, and the very best players learned to gather the balls into a corner and score hundreds in a row with tiny nursing strokes — a marvel of control, but tedious to watch. By fencing off the easy regions, balkline forced players to open the table up and made matches a real contest again. The same instinct later produced three-cushion, the most demanding answer of all to the nursing problem. You can trace that whole evolution in our history of carom billiards.

Balkline today

Balkline never disappeared. The UMB and the European confederation still run cadre championships, and in France, Spain, the Netherlands and Germany it remains a respected league discipline with its own specialists. For a three-cushion player it is superb training: the balk-space rule sharpens your feel for sending balls precise distances, and the habit of never leaning on one repeated stroke transfers straight back to the open game. See how the carom disciplines fit together in our guide to the rules of three-cushion.