Rod Burr's remark in his review of our modern rules in Vol. I No. 5 of THE COURIER that we in W.R.G. restrict our options by consistently using only six-sided dice prompts me to explain why. Firstly, I do own other kinds. When decimal dice first came on the market, I was among the first to grab a pair, and then started to look for ways to exploit them. Well, so far I haven't found anything I want to do with dice that I can't do sufficiently well with cheaper and more easily available six-siders. Consider the ways that you can use dice. You can read the score of a single die, add the scores of two or more dice, or you can multiply the score of one by the highest possible score of another, then add the scores of both, the last of these being what you in effect do when using decimal dice to get a percentage. With the first method, you have a maximum of 6 possible results from a six-sider and ten from a decimal die. I say a maximum, because you can reduce the variation by making some sides the same, as we do with the "average" dice used in our ancient rules. With the second method, a pair of six-siders gives you up to 11 possible results and a pair of decimal dice 18, the results then tending towards the median. Three six-siders give you about the same number of possibilities as adding two decimal dice, but the trend towards the median is greater still. The third method gives you 36 possibilities with two six-siders and 100 from a pair of decimal dice. Wargames rule writers usually use pairs of decimal dice to establish what they call a "percentage", but which is more accurately a two figure probability. This is most used in establishing hits from a single shooter and for morale testing. In the first case, the advantages over our modern system with two ordinary six-siders are more apparent than real. We can get down to an accuracy of + or - 1.4%, the decimal dice user to + or - 0.5%. The difference is surely far too small to matter, and we have the advantage that for all but the least likely shots we only have to bother with a single die. In the second case, decimal dice fall down badly compared with a system in which you add the scores of three six-siders. Apart from the way that the added scores group towards the centre, this is due to the fact that you cannot realistically add probabilities. They must be multiplied. A typical percentage morale test has the player throw his dice to obtain a base score, then add or deduct one or two digit figures ending in a 0 or 5 for situational factors. Say a unit has a 50% chance of going into an uncontrolled advance in normal circumstances and feels 30% happier than normal because it is uphill of all enemy and another 20% happier because the beer issue has arrived. Such rules make uncontrolled advance now inevitable, while in real life the probability is 100-50 x 100-30 x 100-20 = 28% that it will not do so, 72% that it will. What the rule writer should have done is find the logs of his probabilities, used them instead of percentages as we do, then the player by adding the logs is multiplying his probabilities without realising it and without tears. The final results table then translates them back into an amalgamated probability. Unfortunately, the player, not realising what has been done to make his life easier and the rules more accurate, will probably then go for a set using percentages, since "everyone knows" percentages are more scientific! Back to Table of Contents -- Courier Vol. 2 #1 To Courier List of Issues To MagWeb Master Magazine List © Copyright 1980 by The Courier Publishing Company. This article appears in MagWeb (Magazine Web) on the Internet World Wide Web. Other military history articles and gaming articles are available at http://www.magweb.com