“A Closer Look at the Meyer Dice Tube”
by: Chuck Bower
What is a Dice Tube?
A recent addition to backgammon equipment is the dice tube for generating dice rolls. Charleston, SC club director Brett Meyer has spent considerable time over the last five years tinkering in his shop, and his current Meyer Dice Tube, Version 2 is reviewed here.
I begin with objective information and cautiously finish with subjective opinions. There has been (to me) a surprising amount of misleading information from both proponents and opponents of this device. My intent is to cut through the noise and present a signal.
In a nutshell, the dice tube is a 9-inch (230 mm) tall, clear acrylic cylindrical tube about the diameter of a typical dice cup—2-inch (52 mm) inner diameter with 1/8 inch (3 mm) wall thickness. Both ends are capped with acrylic disks, surfaced on the inside with Velcro hook fabric. A stairstep series of soft rubber latex baffles are located in the central 55% of the tube.
There is a website with information on Meyer's device: http://www.brettmeyer.com/. The 2-minute video there shows the proper rolling technique. A nice feature of this video, which is in slow motion, is to demonstrate the action of the dice as they work their way from one end of the tube to the other, interacting with the baffles along the way.
Two versions of the dice tube are manufactured, one with sealed end caps and the other with removable end caps, allowing for the inspection and changing of the dice. For tournament backgammon play, the second type is recommended, and that is the device reviewed here. (I have played a match with a Version 1 sealed tube and encountered no problems.)
Use of the dice tube in conjunction with a chess clock is a natural combination. Since clocked backgammon is played using only one set of dice, and the player indicating the completion of his turn by punching the clock, substituting the dice tube (and its single pair of dice) for two cups follows seamlessly. For non-clocked backgammon, a player indicates the end of her turn by tapping the top of the dice tube rather than picking up the dice.
In both cases, an advantageous feature of the dice tube is that it is kept to the side of the playing surface (and out of the way of checker movement) at all times. Compared to conventional rolling, this alleviates the need to touch or move the dice during play.
For over-the-board backgammon in Western countries, the standard, modern method for generating random rolls is shaking precision dice in a lipped dice cup and subsequently rolling them out onto the playing surface. When possible, the pluses and minuses of each method should be compared and contrasted.
Time Needed to Roll:
A potential advantage of the dice tube over the conventional method is in time savings. The first study I did compares the time required to generate dice rolls, beginning from the completion of the opponent's turn and until a legal roll (both dice flat on the proper surface).
For the standard method, I used a Robert Neumann walnut cup with 9/16-inch precision dice, tossing them onto a Taki board. I shook the cup three times in an up-and-down motion. Cocked dice rolls were eliminated from the data. I believe this part of the test represents the minimum time required for conventional dice generation, as the soft Taki board surface brings the dice to a halt quickly, and three shakes is the accepted minimum requirement, in my experience.
For the part of this test using the dice tube, I did not differentiate between cocked and uncocked dice (except for one instance when the dice got stuck in the baffles) since the time required to roll from the beginning to the end is the same whether or not the dice cock.
The results for 300 trials each were an average of 3.6 seconds per roll for the dice cup and 1.7 seconds for the dice tube. Based upon a previous study, this translates to a time savings in a typical 7-point match of between seven and eight minutes. (See www.bkgm.com/articles/Bower/ClockExperiment.html.) In addition, the occasional time-consuming search for dropped dice with conventional rolling does not occur with the dice tube.
One legitimate question I've heard regarding the dice tube is, "Does it deliver random rolls?"
The second study I performed was to record a series of rolls with the dice tube and look for two types of potentially (and physically) fundamental flaws in dice rolling—repeat dice and flipside dice. A repeat die is one that shows the same number on the subsequent roll, and a flipside die is one that ends up on the opposite face on the subsequent roll.
Keep in mind that a fair (randomly generated) die will repeat 1/6 of the time and flip 1/6 of the time. My study compared actual results with what was expected. Here I tracked the two dice (different colors) independently, but rolled them simultaneously (per standard backgammon).
972 data points (that is, instances of consecutive non-cocked rolls with two dice) showed the black die repeating 147 times and flipping 163 times. The white die repeated 172 times and flipped 170 times. The expected numbers for each of these is 972/6 = 162. All four recorded values fall within the 95% confidence interval of 139 < M < 185.
Given the amount of time required for this type of investigation, I did not do a similar study of the conventional dice cup generation method.
During the random dice study I also recorded the number of cocked dice. In 999 rolls the dice cocked 13 times. There are three ways to get cocked dice with the Meyer Dice Tube: (1) leaners—a die doesn't lie flat on the bottom surface; (2) one die sitting physically on top of the other; and (3) a die getting caught in the baffles. Of the 13 cocked rolls, 12 were leaners and one resulted from both dice getting caught in the baffles.
Here I also did not investigate cocking of the dice with dice cup rolling. This is strongly dependent not only on the equipment, but also on the technique of the individual roller, so such a study would require a wide variation in parameters and the resulting large amount of invested time.
Another positive benefit of the dice tube is that it resolves problems that some players might have with finger dexterity or arm flexibility. Although this feature is not widely needed, for cases where it is the value is significant.
Handling of the Tube:
Now I proceed to the more subjective part of this article. First off, it is important to understand that proper handling of the dice tube is important, but no more or less important than proper handling of a dice cup.
For ensuring integrity of the dice generation process, it is important to rotate the tube quickly and remove one's hand before the dice reach the bottom of the tube. As shown in the video, the proper technique involves grabbing the tube with one's hand oriented with the thumb down. The reason has to do with the rotational freedom of the human arm. (Try it both ways and you'll quickly see what I mean.)
Also, there is the tendency among some users new to this device to fear that the tube will tip over, and they try to grab it after letting go. This concern is unfounded, and the action should be discouraged. I have used the dice tube for generating over 3,000 dice rolls, and I've seen my opponents roll with it well over 500 times. Only once have I seen the tube fall over, and that was before the dice had reached the bottom. Upon this rare occurrence, a simple reroll is required.
A couple other concerns I've seen online or heard in person are worth mentioning. One of them is noise. Again, a proper study would involve sound-measuring equipment. As always, measuring the noise generated by conventional rolling should also be compared. Subjectively I've noticed less noise from Version 2, which uses soft rubber baffles compared to Version 1, which had hard acrylic baffles.
Setting the tube down on the table (next to the backgammon board) which in the process of rolling can produce a noticeable thump, depending upon the table's surface. Serendipitously I found that the velour playing surface on a taki board is ideal for eliminating this sound. Recall, though, that since the tube is always used to the side of the board, you can't take advantage of this feature.
There is always present a concern about cheating in backgammon. In theory, every dice generation method can be compromised. In my opinion, the debate over which method is less likely to be vulnerable to cheating is a worthless exercise, fraught with unscientific arguments. Vigilance is the best deterrent, regardless of the suspected cheating method.
The final issue I bring up is an aesthetic one. Some people derive gratification from shaking the dice. It can serve as a release of frustration. There may be a kind of trancelike pleasure for some in the repeated motion of shaking the cup.
To compare two modern forms of play, face-to-face backgammon with its tactile stimulation of touching and moving checkers and cube is different from the more restrictive activity of using a keyboard and mouse.
Even in the supposedly advanced 21st century, there are still some players who believe they have some kind of psychokinetic influence over the dice. (Of course, shouldn't they be able to transfer that power to the dice in a dice tube?)
Whether these desires are based upon reason or not, enjoyment of the game is a requirement. I suspect these non-technical components of the debate are really what will influence how much the dice tube is used in the near future of backgammon competition.
Chuck Bower recently retired from his career as an astrophysicist at Indiana University.
His focus is now on software for sports analysis. He was the 2002 Michigan SummerChampion, 2010 Pittsburgh Doubles Champion, and 2011 Chicago Open Champion.