Setting traps with Red & Blue dice mechanics

I could have called this post "emergent dynamics with opposing die rolls", but then we'd miss out on the fun of setting up a trap and seeing what comes around for lunch. I'm going to talk about delaying the success roll until something actually steps on the trap, but still having enough information on the outcome to know what to lure into the trap.

In a previous post I talked about the opposing die rolls in Red & Blue dice mechanics and the feature of keeping the outcome secret while still giving the players a hit of the task performed. Now before you go all ballistic about fudging dice and keeping die rolls hidden and what not, let me tell you that this time around I'm not going to hide the die roll. Well I'm not going to hide it behind a GM screen that is, I'll hide it in time by rolling only when the prey steps on the trap. How's this different from a single open roll? Read along, I'm about to get to that point.

In many games the GM sets a task difficulty and the players roll against it. The outcome of this roll dictates the result. Did the trap catch the prey? Did the prey get away? Yet it fails to inform the player how well did the character set the trap! We do know that against a specific prey the trap failed or succeeded, but was it due to the size, skill and cunning of the pray or the quality of the trap?

This is where the Red & Blue split dice mechanics come into play. The player rolls for the character's skill regardless of the task difficulty. If the character is an expert hunter then the roll with be done with a very favorable set of dice. On he other hand if the character is just figuring things out, or worse yet applying something seen in a movie, the roll will be done with a less favorable set of dice. What's important here is that the character has a clue as to how well the trap was set. Did the setting favor the character with all the materials? Is the branch strong enough? Was there good rope at hand? Is the counterweight heavy enough? Those are things the character can see and from them conclude the quality of the trap.

Now we move onto the prey. The game mechanics contemplate the usage of 4d6 plus a set of subtracting dice depending on skill. Since this is beyond the scope of this post I'll make an example with 2d6, 3d6 and 4d6, dice sets we are more familiar with.

Let me equate simple trap knowledge with rolling a 2d6 and expert with rolling 3d6. Let me also equate the difficulty of catching a rabbit to 2d6, a fox with 3d6 and a boar with 4d6. Now, the expert hunter sets a trap, the player rolls 3d6 for the skill check and gets an 8, a sad roll indeed (not much better than a basic skilled hunter rolling 2d6). Maybe nature wasn't on the hunter's side this time, the rope at hand is too thin, the trees to weak, whatever. The hunter knows the trap is not the best he's set. With this information at hand the player then decides what to lure into the trap. A rabbit which will feed the party a day at best? A fox that will supply the party for a few days? Will the character risk the trap against a boar which would feed the party for a good two weeks?

The player decides to go for the rabbit. It's better to have at least some food than none at all, and the party needs to keep moving. Hopefully the hunter will have better luck next time. Thus the party works on luring a rabbit into the area, the GM rolls 2d6 at that point and gets a 7. Since the 8 for the trap beats the 7 the rabbit is caught and the party gets to eat that night.

A day later the party has moved along the forest and sets camp again. The hunter sets up a trap and gets a 15! A very good trap indeed! More confident of this setup the party goes on to lure bigger prey. The GM can make things interesting by rolling for what prey there is at hand. A boar is presented by the GM to the party. Will the party lure it or let it pass in favor of some smaller prey?

You finish the hunt. If your party decides to try and capture the boar roll 4d6 against the 15 for the trap, if you decide to lure a fox in then roll 3d6. Good luck with your hunt!

Read more about this by downloading the latest playtest release of Saints & Sinners

Save vs nuke or die

There are certain skill checks whose outcome is unknown until the inevitable happens. Disarming a nuke before opening the case that would set it off. Disabling the ICBM's warhead before it launches. If these things don't get done right it will be too late later on.

So, how do you handle this with your players? More important than that how do you handle dice in these situations?

Let me present a few scenarios:

1. Rolls is done in the open against a target value GM previously mentioned.
2. Rolls are opposing. Player rolls and GM rolls. The player can see the player's roll but no the GMs. The GM keeps the roll secret until the player decides.
3. Rolls is done in the open against a GM set value, but it is hidden from the player (inside a cup). The roll is revealed after the player decides to open the case or not.
4. Rolls are opposing. Player rolls and GM rolls. The player's roll is done in the open, but the GM's roll is hidden and can't be touched by the GM until the player decides.

These examples go from total disclosure to the player (roll 1) and given the player the option to decide based on that outcome to having no clue as to what happened (roll 3). Rolls 2 and 4 can give a hint of how well the character did, but the player can't be sure the roll succeeded until the GM reveals the roll. Roll 4 leaves no room for fudging as the GM can't modify the roll.

What's your thought on each? How would you handle each situation? Do you prefer a open roll over the hidden? Do you want to at least know a little of your outcome? How to decide otherwise right?

Fairy tales are devoid of player agency

If I look at fairy tales from the classic player agency definition I'd conclude they're devoid of such player agency. After all the princess will prick her finger on the spindle no matter what. Some players would argue that it's railroading. No matter what the players do the door will be closed, no matter what passage they choose to go down it will lead to the same room, no matter what they do the story leads down the same inevitable road.

If something is to be learned from Maleficient is that the GM is also playing a character and that destiny is full of surprises.

In the classic story line the fairy/witch is a evil GM controlled character sent to make everyone in the kingdom miserable, specially the small and defenseless princess. I can imagine many players complaining about the unfair GM who, no matter what they do, always ends up pricking the princess with the spindle. "It's unfair!", they'd say. "We've journeyed east and west, north and south, we've brought everything onto the evil fairy, we've taken the precaution to lock the princess on that dreadful day to be, and still there's a fucking spindle! Come on! Give us a break you're just being a shitty GM and railroading the adventure". I can hear them say that and worse. Can you?

But there is Maleficient! A story with the same railroading. The princess will prick her finger on the spindle no matter what. Yet the story unfolds entirely different. We see a more complex antagonist. An antagonist who is full of dreams and hurt by having these dreams clipped. An antagonist who is an antagonist from the point of view of the men in the castle, who in turn are antagonists to Maleficent. So regardless of the inevitable destiny involving the spindle there is so much the players can do in between, so many internal struggles that can add to the story and so many ways to end the story. So many ways to come to a new and totally unexpected story.

So next time you complain that the GM is railroading the adventure because no matter what you do as a player there are things you can't seem to change, take a moment to think which Sleeping Beauty story are you living with your character. Are you rehearsing the same ol' Disney version or are you forging a new Maleficient?

Red Blue dice mechanics

Red & Blue is a dice mechanic I've been using in my latest games and it's at the core of the Saints & Sinners game. It uses up to 9 d6 in a combination of red and blue dice. The red dice represent the strength of your roll and the blue the weakness. The system revolves around opposing die rolls, one roll for the task being performed, which represents its difficulty, and one roll for the skill with which the task is being performed. The level of success is measured by how much the skill roll overcomes the task roll, and obviously failure is quite the opposite.

Now, to measure skill and difficulty blue dice are added or removed. The easier the task or the more unskilled the character the more blue dice the roll has. This makes for a very nice treat for players, the more skilled your character is, the less dice you have to roll and add. How many dice mechanics do you know that give you that benefit?

How does the Red & Blue mechanics work? Well on one end of the spectrum we have the unskilled character and the trivial task. They roll 4d6 - 5d6. That is we add 4d6 and we subtract 5d6. This might be a daunting task at first, but being d6s they cancel out quite quickly and you end up adding and subtracting very few dice.

In the roll the 4d6 are always constant, they're the red dice that are always added. The blue dice are subtracted from the red and as the skill increases we have less of them. Skills go as follows (amount of blue dice is noted in parenthesis): unskilled (5d6), skilled (4d6), professional (3d6), expert (2d6), master (1d6) and legendary (0d6).

Tasks follow the same pattern: trivial (5d6), easy (4d6), challenging (3d6), demanding (2d6), hard (1d6), epic (0d6). The first thing to notice is that there is no fixed difficulty value. It's a range that will depend on the roll. Not all tasks are equal and I've found out that this adds an interesting twist to things. The hardest of the easy tasks are similar to the easiest of the challenging tasks.

Players commit to the human term. As a GM I'll inform them the task is challenging. If they take it the dice are rolled and the difficulty is set. The player's roll must equal it or better the GM's to have success.

Success and failure is further divided into outstanding success and outstanding failure. If the skill roll beats the task roll by 10 or more then it's an outstanding success. If on the contrary it fails by -10 or less it's outstanding failure. These outcomes are interpreted according to the task and situation and hand. I will note that in combat there's a "specialization" of these rolls in such a way that a single roll reveals the outcome as miss, suppression, hits cover, hits target (and to what degree). In hand to hand combat these outcomes indicate how attacks are chained together, who does damage and who takes the lead. As you can see with such a broad spectrum of outcomes it is easy to customize the roll to your needs as a GM.

What features does the Red & Blue mechanics have?

1 - They have a lot of points so it's easy to add modifiers and not go off the chart. That is to saturate the roll in such a way that success or failure is guaranteed.
2 - The rolls behave in a way consistent with what you'd expect from higher skill. As skill increases the average value increases and the variance decreases. The rolls become tighter around the average. This is consistent with skill. The better the skill the less variability we should be expecting.
3 - As a GM you can maintain a level of secrecy from the players. There's no fixed difficulty from which they can immediately conclude if they succeeded or failed. Did you defuse the bomb? Only one way to find out. This adds tension to the game and makes it feel like a real action thriller.
4 - As a GM you don't have to mess with abstract values and target values. It's simple. If you think the task is difficult well just roll those dice and be done with it. Its very easy to convey the idea of difficulty and challenge.
5 - Teamwork. This is beyond the scope of this post, but I'll say that the mechanics include a means to determine the overall skill roll for a group of characters participating in a task. This is a really nice feature to promote teamwork among players and build multidisciplinary groups.
6 - Initiative. Another topic that's a bit beyond this post, but I'll say there's a clear rule to convert skill to time and back. This allows the player to take chances and convert odds of success to speed.
7 - I've said it before and I'll say it again as a closing point. The more skilled your character is at something the less dice you have to roll.


Take a look at these dice at work by downloading the latest playtest release of Saints & Sinners

If you knew the weapons to come

This year in Back To The Future, Biff Tannen takes the Gray's Sports Almanac and returns to 1955 to become a millionaire by betting on all sorts of sports events.

What if your character got a copy of this year's Jane's Books and went back to 1955 to let the superpowers know what's coming?

What challenges would your characters face? What an opportunity for fortune and fame would this lead to! To know what weapon systems the enemy will have 20 or 30 years from now.

Thoughts? Who would you contact? How would you convince them? How much would you ask? How would you explain yourself? What would you have to do to stay alive?

Floating target values in action thriller games

Action thrillers are packed with high levels of anticipation, uncertainty, surprise, anxiety and terror, so it sucks to know you character disarmed the trap before opening the case! Knowing my character succeeded the roll kills all uncertainty and smothers any anxiety and fear of actually going ahead and opening it. On the other hand I can't just open it blindly, I must know if I succeeded. There has to be a middle ground between being totally uncertain and somehow know I did a good job at disarming it. It is here that floating target values and split dice mechanics come into play.

Floating target value is a term I use to refer to cases when a roll needs to beat another roll. The target value will fall within a range and the player doesn't know this until the GM rolls. Thus the term split dice mechanics. The player rolls dice, the GM rolls dice and the outcome is successful if the player's dices beat the GM's, but the player doesn't know what the GM rolled! The player may know their roll was good or bad, but can't be certain of its outcome without knowing the GM's roll, and so the tension builds.

I'd like to make a clarification that has been pointed out by many readers after I posted this article. Floating target differs from opposing die rolls in that the later is a subset of the former. Opposing die rolls require one roll to be above the other. A floating target can also be a proximity value,  for example 2 below or above the value rolled by the GM. This makes it harder to guess! From the previous example if I roll 2d6, in a roll equal or over opposing mechanism a 10 is pretty good and a 12 is unbeatable; in a proximity roll within 2 anything goes, a 4 is good if the GM rolled 2,3,4,5 or 6. If the GM rolls an 8 then the values for me to win would be 6,7,8,9 or 10, a truly floating target!

The Saints & Sinners skill mechanics is based on opposing die rolls. Characters have a skill level that determines which dice to roll and tasks in turn have their difficulty rating and their corresponding set of dice. The player rolls, the GM rolls and the outcome is resolved based on the difference, but only the GM has both parts of the puzzle and can thus leave the player guessing. Did I type the correct stargate coordinates? Was the trap disarmed? Was the bomb defused? Did I hit the monster behind the wall? Did my machine gun fire hit anything in the bush behind the tree line? Who moves in to investigate? Who opens the door? Who goes beyond the event horizon first?

Drawback? Well it requires a bit more rolling and comparing, after all nothing beats rolling a d20 and seeing if it beats a target value. Pros? When it comes to thrill, nothing beats not being certain of the outcome of a dangerous task such as disarming a bomb! No matter how much players might say they don't metagame, they will, even a tiny little itsy bit. This way the GM gets to keep the result secret without depriving the players of their opportunity to roll for their character. Personally, its worth the overhead! What do you thing? How do you keep your players on their toes?

Airplane flight random encounter table

Airplanes are deemed too enclosed and compact to consider random encounters on board. Nothing is more distant from the truth. In this day and age of air travel random encounters in an airplane are an important aspect of any modern setting rpg. They can provide something for the characters to do in an otherwise boring transoceanic flight. Not to mention a plot twist!



Roll 2d6 and determine the random encounter


2  Liam Neeson
3  Alien
4  Zombies
5  Rats (and 2000 nibbled boarding passes)
6  Vampire(s)
7  Gremlins
8  Snakes
9  Ghost
10 Virus
11 Ex-wife / Ex-husband
12 Hugo 'Hurley' Reyes

d20 & uncertainty

In my previous article I touched on the topic of information entropy and explained how certain resolution mechanics can be considered random even when dice are not involved. I explained how information entropy is a measurement of the amount of information in a message. I supported this with an example of a coin and how a fair coin has an entropy of 1 and a coin with two heads has an entropy of 0. Such a coin will always land heads, we know what will happen before we flip it and such an event provides us with no information whatsoever.

Now it's time to take a look into something more interesting and commonly used in our hobby, the d20.

What's the information entropy of the d20 as the target becomes harder to hit? What does this mean to us players, GMs and designers?

First I'll build a table with the required roll to hit and the odds of failing and succeeding in an attack. The following table shows the required roll, the odds to hit, to miss and the entropy (calculated by the sum of the log of all that stuff you don't want to read about here).

d20
required roll	failure	success	entropy
8	35.00%	65.00%	0.93
9	40.00%	60.00%	0.97
10	45.00%	55.00%	0.99
11	50.00%	50.00%	1.00
12	55.00%	45.00%	0.99
13	60.00%	40.00%	0.97
14	65.00%	35.00%	0.93
15	70.00%	30.00%	0.88
16	75.00%	25.00%	0.81
17	80.00%	20.00%	0.72
18	85.00%	15.00%	0.61
19	90.00%	10.00%	0.47
20	95.00%	5.00%	0.29
21	100.00%	0.00%	0.00

Notice how the roll reaches maximum entropy at 11 when the odds of failing or succeeding are even and then begins to drop, eventually reaching zero at 21, a point in which it makes no sense to roll as failure is guaranteed. Graphing the values from 1 to 21 I get the following curve.

Since entropy is a measure of uncertainty it is easy to understand how it drops as we approach the edges. If my character needs a 2 or better to hit there is little uncertainty as to what will happen the next time it's my turn, on the other hand if I need a 20 or better it is quite certain I will miss, and if I need a 21 or better I'll surely miss! No need to even roll! Entropy is 0 and actually rolling the die provides me nothing new. As a player or GM I will discover nothing by rolling a d20 when I need a 21 to succeed.

Let me make another example to show this. Let me write out a succession of attack rolls. I'll write F for fail and S for success. When the odds are even or near even, that is anywhere between an 8 and 14 is needed to hit, the string of outcomes would look something like this:

SFSSFSFFSFSFSSFFSFFSSFSFSFSSFF.....

There's a pretty even occurrence of S and F.

If on the other hand I move to the right of the graph and require an 18 or better the string will look something like this:

FFFSFFFFSFSFFFFFFSSFFFFFFSFFSF.....

There will be considerably more Fs than Ss, there might be two successive Ss, but these will be uncommon and far in between.

In the extremes the strings will look like the following, either:

SSSSSSSSSSSSSSSSSSSSSSSSSSSSSS.....
or
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFF.....

There is no uncertainty, my character will either always succeed or always fail!

Why is this important? Well it can save us a lot of time. Why make all those extra rolls if I know I will most surely succeed of fail? Obviously I can't guess the future and knowing I'm going to fail very often doesn't spare me the roll because I need to roll in the odd chance I do succeed. What I can do is compare this to other roleplaying mechanisms, for example drama which relies on the player narrating the outcome. An equivalent event is my options getting reduced more and more. More often than not I as a player take the next tunnel to the right instead of considering the other options. The lower the entropy the less options I really have available to me. I'm getting less bang for the buck as I still have to roll the dice.

So, what happens when we include more outcomes?

Lets revisit the above table and pick out a few values (11, 16 and 19) and calculate the entropy when 1 represents critical miss and 20 a critical hit. The following tables include the contribution of each individual outcome to the the total entropy of the roll. Let me explain based on an 11 required to hit when rolling a d20. The odds of hitting or missing are 50%-50% (11,12,13,14,15,16,17,18,19,20 hits, all other miss), but a 1 is a critical miss and a 20 is a critical hit. In the previous example the maximum entropy was reached at 11 and the value was 1. Now at 11 the entropy is 1.469, almost a 50% increase because we included other outcomes that add information to the roll. There are more outcomes thus there is more uncertainty as to what will happen. As the roll required to hit increases the entropy decreases; 1.257 when a 16 is needed; 0.848 when a 19 is needed.

d20 tohit 11	odds	entropy
crit miss 1	5.00%	0.216
failure	45.00%	0.518
success	45.00%	0.518
crit hit 20	5.00%	0.216
	100.00%	1.469
d20 tohit 16	odds	entropy
crit miss 1	5.00%	0.216
failure	70.00%	0.360
success	20.00%	0.464
crit hit 20	5.00%	0.216
	100.00%	1.257
d20 tohit 19	odds	entropy
crit miss 1	5.00%	0.216
failure	85.00%	0.199
success	5.00%	0.216
crit hit 20	5.00%	0.216
	100.00%	0.848

What's interesting to see is what happens with the individual elements. The critical outcomes always add .216 bits of entropy. When a 19 is required the failure outcome, which accounts for 85% of the odds, represents only 0.199 of the entropy; success and critical success have equal uncertainty (entropy). This is counter intuitive. It makes no sense to believe that an outcome which is barely possible (success) is equally important than one which should be considerably less probable. After all if my character can hardly score a hit how can I explain that one out of two hits will be critical and will have some outcome like double damage? It is this that give me the jolt feeling when I use the d20 in games. When the character is too weak to take on a challenge or too strong I get the feeling I'm rolling a lot for a whole lot of nothing and every so often I get these radical, very impacting outcomes.

Lets up the stakes a little bit and introduce a variable critical hit and miss. Instead of 1 being critical hit lets make it to hit minus something and consider two scenarios: a) tohit - 10 and b) tohit - 15, and 1 is always critical.

The following tables show the numbers for a tohit roll that requires a 19 or better to hit, but a critical is generated on a 4 (tohit-15) or a 9 (tohit-10).

d20 tohit 19	odds	entropy
crit miss 4	20.00%	0.464
failure	70.00%	0.360
success	5.00%	0.216
crit hit 20	5.00%	0.216
	100.00%	1.257
d20 tohit 19	odds	entropy
crit miss 9	45.00%	0.518
failure	45.00%	0.518
success	5.00%	0.216
crit hit 20	5.00%	0.216
	100.00%	1.469

Notice how just going from 5% odds of a critical to 15% odds of a critical has increased entropy from 0.848 to 1.257. There's a whole lot more going on in that roll now. Things get interesting when the player has to decide to roll or not against low odds of success and a lot higher odds of critical failure. Notice also how taking those same odds for a critical miss and increasing them to 45% doesn't increase entropy that much more! There's a sweet spot after which it may be just too unfair.

Now let us not forget this is symmetrical and the same happens for critical hit! Doing the numbers for a superb character that hits on a 3 or better we get the following tables, one is the plain old 20 for critical hit and the other is the tohit+14 giving the player a critical hit on a 17 or better.

d20 tohit 3	odds	entropy
crit miss 1	5.00%	0.216
failure	5.00%	0.216
success	85.00%	0.199
crit hit 20	5.00%	0.216
	100.00%	0.848
d20 tohit 3	odds	entropy
crit hit 1	5.00%	0.216
failure	5.00%	0.216
success	70.00%	0.360
crit hit 17	20.00%	0.464
	100.00%	1.257

When my character gets really good the behavior repeats itself, entropy drops drastically without the adjusted critical ranges, and I'm left rolling dice for a whole lot of nothing. My character is mowing down goblins left and right and every so often he will do a critical that will either chop three goblins with one blow or chop his leg off.

With the adjusted critical hits my character is going to be impaling three or four goblins way more often, he'll push one and throw the three behind him down a wall, he'll swing his sword around and behead two goblins at the same time, etc. You get the idea, there is more going on in the story than there was before.

Conclusion, I reviewed the d20 roll looking at the measure of its uncertainty as indicated by the entropy of the roll. I showed how outcomes become monotonous when skill is either too high or too low and thus added two more outcomes: critical hit and critical miss (as is commonly used in our games). I once again studied this as skill increased or decreased considerably and noticed how the usage of a fixed value for critical outcomes once again lead to monotonous outcomes. I adjusted this by using a variable critical, which lead to an increase of entropy once again. I compared two settings, a 10 point difference and a 15 point difference (critical miss on 4 and 9 as explained above), and noticed that the 15 point difference was good enough and the 10 point difference made it too uncertain between fail/critical fail or success/critical success, that is the odds for a normal outcome vs a critical were the same, when it's more intuitive that critical outcomes should have lower odds than normal outcomes.

After seeing these numbers it's my conclusion that using critical outcomes at -15 or +14 from the required to hit (with 1 and 20 always being critical) makes for the best d20 rolls for OSR styled games. It adds enough uncertainty that it keeps things interesting without making it so uncertain it becomes a wild guess. If I look back at the table for a tohit of 11 I see the following:

d20 tohit 11	odds	entropy
crit miss 1	5.00%	0.216
failure	45.00%	0.518
success	45.00%	0.518
crit hit 20	5.00%	0.216
	100.00%	1.469

As  my character gets better and I only require a 3 to hit I get the following

d20 tohit 3	odds	entropy
crit miss 1	5.00%	0.216
failure	5.00%	0.216
success	70.00%	0.360
crit hit 17	20.00%	0.464
	100.00%	1.257

The odds of hitting have gone up from 50% to 90%, and the odds for a critical hit has gone up to 20%, while the overall entropy has dropped only to 1.257 instead of .848 as it did before. This small drop is due to the uncertainty of hitting being removed by my character's skill. I'm more confident I'll get what I want, to win! But at the same time I'm filling the gap with more information from the critical success which is now a more important element in the story than it was before. Entropy should drop due to skill, but not so much that it steals from the story!

Well wow, just realized how long this post turned out. I hope you're still with me and that this has been helpful. I'd love to get your feedback on this and know what you're doing to get a little more from each die roll on your table.

Drama, Karma & Fortuna are all random mechanics

Drama, karma and fortune are three resolution mechanism commonly cited in game design theory, such as GNS. Fortune is the one renown for its randomness, chance, as they say, determines the result. Over the last few months I've had conversations with avid supporters of GNS and drama, karma and fortune as means to categorize resolution mechanics, and what's called my attention is that they're in the understanding that only fortune (dice, cards, etc.) brings randomness to the game.

My position is quite the contrary. All three are random processes, being drama the one with the most unpredictable outcomes, after all dice can't roll on more sides than they have, right? Yet players can select from a nearly infinite set of options in a tabletop RPG. My intent in this article is to go over the three mechanisms, review them from the angle of information entropy (uncertainty) and see how we can see all three as random resolution mechanism.

A quick review, what is drama, karma and fortune? The abridged version of it is that drama is the resolution by means of players narrating the outcome; karma is the resolution by means of comparison or expenditure of some value; fortune is the resolution by means of random value generated by dice, cards, etc. It is common practice to call this last mechanism as "uncertain" or "random", but it's not the only one. Drama and karma are also random, that is there is uncertainty of their results when such mechanisms are applied.

To prove this and show that drama and karma are mechanisms with a degree of uncertainty in their outcomes I'll take a moment to touch on entropy, namely information entropy or Shannon entropy. Information entropy characterizes our uncertainty about our source of information it is the average amount of information contained in each message received. This sound a bit confusing at start, information, uncertainty, messages? What's this got to do with tabletop rpgs? Well it is really easy to explain with a coin. A fair coin has a 50-50 chance of landing heads or tails. A coin with two tails has 0% chance of landing heads. I'm certain that every time I flip it it will land tails. The outcome is certain, there is no uncertainty in the action and the action provides me no information that I don't already know. In other words flipping the two tailed coin is pointless. This behavior is illustrated in the graph below. It measures entropy as a function of the odds of landing heads or tails. A truly fair coin is in the middle, a 50-50 chance yields maximum entropy ( a value of 1). To the left and right of the graph a 0% or 100% chance (two tailed or two headed coin) yields zero entropy and thus zero information. The X axis (Px) represents odds, the Y axis (H) represents entropy.

Now back to drama, karma and fortune. I've already mentioned that fortune is random and it creates a degree of uncertainty in the game. A good example is the coin flip I just gave. But what about drama and karma? How can they be random processes and provide uncertainty in the game? This is contrary to much of what we hear: dice on one end, storytelling on the other. Now, lets consider that karma and drama are indeed non-random mechanisms, that they provide no uncertainty. If so then their entropy is zero, just like the two headed coin. If they provide no uncertainty in the game they also provide no information, they add nothing to the story. Why then do we use them? Why then do we go through the trouble of using them if we know their outcome prior to their usage? The only reasonable conclusion is that contrary to the beliefs of some, karma and drama are random and have an uncertainty just like dice do. The question is how much more or less uncertainty!

Information content and entropy are things I seldom see touched when discussing game design. What's the overall value of die roll? Of the player's words? Of those numbers on the character sheet?

Over a series of upcoming posts I'll look into die rolls, their entropy and the effect of modifiers on the overall impact on a story. What is acceptable uncertainty in a storyline? If you look at the graph above you'll see that success rate drops at a different rate than entropy. Uncertainty is not the same as odds of hitting it with an ax!

What do you think? What makes things unpredictable, uncertain and possibly "not fun" in your games and what makes for "very fun" in your game? How far do allow things to become predictable in your games before it's just plain boring or railroading?

Entropy and resolution in tabletop RPGs

Entropy, information entropy, is the average amount of information contained in each message received. It is a measure of uncertainty. What does this have to do with tabletop RPGs? Well we'll constantly sending messages during our games, aren't we? The GM says something, players respond, the dice are rolled and the story evolves.

Now if something has zero entropy it has zero information. An example of this is a die roll that always fails or flipping a coin with two heads. You know it's going to fail, why roll? You know it's going to land heads, why flip it? Taking 20 is also a zero entropy event, you know you'll win. Just skip the bull and tell me the story already.

Why do I find this important? Well we're usually used to handling odds of success or failure in our games. Like 17 or better on a d20 to do something, or roll 10 or better with 2d6, etc., you get the idea. We usually think of these as random events, but they're not the only ones, and entropy is quite different from odds of success or failure. They're linked, but not the same. A small chance of success can still add a significant amount of entropy and thus uncertainty in a game. So where do we draw the line? At what point do we stop rolling dice and just rule the outcome?

Well you see, the catch is that ruling, GM fiat and fudging dice is also a random events. It's a human controlled random event, but random nonetheless because as a player I can't know what the GM is going to rule a priori. As a GM I can't know what my players are going to do. I don't know if the player will use a bennie or not.

Entropy is something I seldom see brought up when talking about resolution mechanics. In upcoming posts I'll look into some game mechanics and dice rolls and look at the entropy involved. Do these actions add to the story or just distract us with needless activities?

Afrika Korps' stolen treasures

Cairo 1940, the continued presence of British troops in Egypt is in question. With Axis powers pressing down and the battle of El Alamein still not here, the future is uncertain. Nonetheless you've been sent to Alexandria to investigate a blackmarket art trading route that is "exporting" precious works for the Fuhrer's Führermuseum in Linz.

So far three brave souls have joined the quest, an art expert specialized in medieval art, a yuppie art student turned forgery artist and a Renaissance architecture expert. They're now enjoying coffee and tea in a shop across the street from a business involved in the illicit trade of goods. Their contact, a liaison so called Aamir, is pointing them in the direction of potential smugglers, but what is his role and why is he cooperating with the British?  Is he really interested in helping Her Majesty's secret services or is he getting rid of unwanted competitors?

Four men are working on a plan to contact the store owners, obtain information, gain knowledge of the ledgers and any information that can grant them a means to stop the Third Reich and recover the Afrika Kors's stolen treasures. The adventure is just starting! Today it's Africa, tomorrow Monte Casino and hopefully someday the Fatherland itself.

I'm really excited about today's first session of Indiana Jones themed and Monuments Men based WW2 campaign of Saints & Sinners. I'm sure the upcoming sessions will bring lots of thrill and excitement in the world's greatest treasure hunt of all! Recovering the western world's greatest cultural treasures from the grip of the Nazi SS.

PS, did I mention one of the characters is expert in the occult? Who knows, maybe we'll stumble upon some real magic and ancient relics!

Initiative in an action thriller game

What's the role of initiative in an action thriller and how does this relate to character skills? In my recent experience initiative is a key element in game mechanics that brings out great stories and one aspect of game mechanics that hasn't been exploited as much as it could.

Seldom have I seen games that focus on determining exactly when something happens. On one end of the spectrum there's a lot of work done on detailed weapon damage, range, bonuses, modifiers, hit locations, etc.; on the other there's a quest for a simpler and faster conflict solving mechanism that focuses more on a fast paced game with easy to learn rules, but that don't really get down to determining when things happen and how the character's skill contributed to this. In both cases initiative is mostly a thing that says you go first, then me, then her, then him and so forth.

I wanted something that had "action thriller" written all over it. So after a year working on the Saints & Sinners game I've come to realize the value of precise time measurements in an action thriller game and how much this can add to a story with such little effort. While I believe a game's mechanics don't make a thriller on their own they sure can add or subtract depending on how they work. Specially if the player has control over this and the decision making process is in itself thrilling.

Action thrillers are packed with anticipation, expectation, uncertainty, surprise, anxiety and maybe even terror. I can't have much of this if my character has high hit points and I'm confident it won't get killed in the first round of combat or two. While games such as D&D can be thrillers at first level they quickly lose this quality as characters level up and hit points increase. Balance, another buzz word in some games, is also a thrill killer. Thus the first thing to go in the game were high hit points and balance. A character can die at any moment. Survival depends on skill and player planning. Balance is not guaranteed by the system, it's provided by the player.

Lower hit points took the game in the right direction making the game more tactical with role playing and planning taking a central role, but still it wasn't enough. There was this gap between the hero and the common minion. An inexperienced NPC could very frequently get a kill out of pure luck, particularly at short ranges where it gets close and personal, and the odds of missing is low. What I needed was something extra, something that was missing. That missing element was initiative as a skill.

Initiative was transformed from a means to determine order of events to an extension of the skill system. It's a product of some degree of randomness (dice), attribute bonuses and skill. Linking skill to initiative and providing a relationship between higher skill or higher speed allowed the unfolding of thriller styled events. Characters now have a means to leverage their skill to gain an initiative bonus. This bonus is in turn a concrete measurement of time. Each initiative point is a quarter second difference in time. If your character is really good, great aim isn't going to help you much at short range. The game allows the player to trade in some skill from the attack roll and convert it into a bonus on the initiative roll. A half second can be the difference between life and death.

Half second and quarter second you say? That's surely got you thinking about how counter intuitive this seems. If I'm resolving things at quarter second intervals even the simplest encounter will take all day. Well that's not the way it's done. Having quarter second intervals doesn't mean players are asked what they do every quarter second of game time. That would be ludicrous. A key element in action thrillers is speed. Without a fast pace you quickly lose the adrenaline rush needed to keep you at the edge of your seat.

What it means is that when facing opponents your character can lower the attack skill and gain a speed bonus. If your character is a grand master with the katana, then two or three levels can be dropped in exchange for initiative bonuses; thus by attacking as a pro or expert your character can gain an 8 or 12 points bonus. If you add applicable attribute bonuses and a good roll that can increase to 16 or more initiative points ahead of the first opponent. Considering that masters such as the bride can have as little as three points to an action a 16 point lead translates to 5 actions before the first minion can even blink. In the time it takes you to figure out the exploding dice your character has killed five guys.

It is easy to see how this can be very advantageous for a skilled hero, but what about bosses? When facing more challenging encounters "mano-a-mano" it requires greater attack and defense skill and initiative will be more on par. In this situation the player places more skill on the attack and defense than on the initiative as now the odds of missing or being hit are a lot higher. But still as a player you can gamble and go for a quick kill, and that's where all the thrill is after all! What will your character bet on this round, speed or skill? Will you risk a weaker defense just to be the first to attack?

Under its modern warfare facade, Saints & Sinners is an action thriller role playing game. It's an easy to learn system and at only 70 pages it's breeze to read and start playing. You can download it here as PWYW. Contributions are, as always, greatly appreciated.

Jun Raqan

Jun Raqan means the one legged. He is the Mayan god of wind, storm and fire. A relentless and temperamental god with incredible power. He is know to level vast expanses of land overnight. His temper follows Kinich Ahau's (sun god) cycle though the skies. Weaker and more reserved during spring as he knows Kinich Ahau is becoming stronger, he quickly becomes confident during the ending days of summer when he knows Kinich Ahau must rest for the winter.


He rises slowly from across the ocean and his arrival is foretold by increased rains and winds. The only god that was involved in all three creations of men is still with us in our modern day and age. We hear of him in the news during those months of fall that foretell the arrival of winter. We know him as Hurricane, the one legged monster from the sea.


Image Source
http://www.pinterest.com/pin/500462577311210281/
http://ldctstormchaser.blogspot.mx/2010/09/hurricane-igor-pictures-from-bermuda.html