Tangent: Exploding Dice and Unlikely Occurances

Something I really enjoy in games is the chance that, under perfect circumstances and/or with a perfect roll, the underdog model or player character or what have you can overcome impossible odds and make the shot, 1-hit-kill the enormous dragon, dodge what should have been a point-blank shot, etc. I also like it when the trope is flipped on it’s head, where there’s a chance to fail so spectacularly that everything is ruined utterly and completely, if you roll/plan badly enough.


A good example of this is exploding dice mechanics, and for this example I’ll use Mantic’s Deadzone. Deadzone uses d8s, and on a roll of 8, you keep the 8 and roll another die. This means with an absurdly good string of luck, one can roll a huge number of successes, enabling a model that might normally never have a chance in hell against a target have a remote chance of actually damaging it or taking it down completely.


Warhammer Fantasy Roleplay Second Edition (WHFRP) and Dark Heresy have a similar thing in that if you roll a 10 for the damage dice (All damage uses a d10, if I recall right), you roll to hit again, and if successful, roll the d10 and add that damage. At that point the d10 can explode, enabling a potentially lucky player to one-shot an otherwise incredibly durable and potent foe.

However, the “exploding” doesn’t need to specifically be “Rolling the maximum on the die means you keep it and roll another die.” I instead see it as any mechanic that allows, if you cross a certain threshold (Typically achieve the maximum or minimum result possible), to increase/decrease the effects, and allows this threshold to be crossed in another or multiple subsequent rolls.

An example of this is the rules for Chaos Manifestations in WHFRP when spellcasting. If a player rolls multiple 1s on their d10s for casting (Again, going off of my memory of the game here), depending on the number of 1s achieved a player gets a Minor, Major, or catastrophic (I forget the term used for the 3rd tier of badness) Chaos Manifestation. However, when you roll to see what occurs for a particular tier of Manifestation, a high-enough roll bumps you up to the next level of Manifestation. Minor tend to be mildly irritating things, like loud noises, curdling milk, temporary weakness or minor damage. Major include more severe damage, small demons appearing, a chance of insanity or mental scarring, and so on. The highest tier can summon greater demons into play that can and typically will slaughter the rest of the party, and the character can suffer extreme damage and possibly be killed outright.

Thinkgeek light-up d20. They look awesome in person too!

Something I want to try eventually is an Exploding Crit system for D&D 4e. D&D 4e currently has a Critical (A roll of 20) meaning all of your damage is maximized. I’d like to offer players the chance to either take that option, or try for an Exploding Crit: They roll to hit again, and if successful, they double the damage rolled (So roll the dice for damage as normal, and double the result). The player can then either keep that, or attempt to increase the multiplier by rolling to hit again. Each additional “hit” increases the multiplier by 1x (So starting at 2x, then 3x, 4x, 5x), but if any of the attacks are missed, the attack deals the absolute minimum damage is can (So 2d6+2 would be 4 damage).

This is because 4e very much feels like a game of attrition alone during combat. Occasionally a Daily and/or Encounter is popped and it helps the fight go a little faster, but barring direct DM fiat, a single player’s round of attacks against a very tough fresh monster, like an Elite or especially a Solo, will not kill it, no matter how perfect their damage rolls are. I want to give players that ability, at the risk of them neutering their damage output.

On a final non-sequitur closing note, I’d like to recommend Ultramodern 4 for anyone who likes the 4e rules and is looking for a good modern/scifi ruleset. It uses the base 4e mechanics for modern/scifi play, and includes quite a few good solid uses of the underlying 4e mechanics, including entirely noncombat classes. I am absolutely itching to play a game using only non-combat characters in the party, and get something akin to Oceans Eleven to overcome everything with a combination of charm, threats, and fast-talking.

6 thoughts on “Tangent: Exploding Dice and Unlikely Occurances

  1. Hi there, firstly simply for the purpose of correctness, wfrp spell casting like dark heresy psychic powers rolls manifestations on doubles, triples and quadruples but otherwise your explanation is correct.

    For me 4e’s intense combat system made roleplaying more difficult, simply due to the vast amount of time people had to be focused in combat, it was difficult both as a player & a DM to switch back and forth. I do like a lot of what has been done for DnD next (5the ed) as I was a playtester but I will have to see how the final system is on its own merits.

    Finally I feel exploding dice are fine in an RPG setting but I dislike them in tabletop skirmish or wargames due to the vast influence they can have which is purely luck based.


    • Ah, thanks! I had thought it was just multiple 1s rolled, not any doubles/triples/quadruples.

      As for D&D Next, I think it has some promise. The use of different dice for skill tests and (iirc) the “power” dice for fighters that they can use with an attack are nice touches. However, I’ve not seen enough stuff that is more engaging to me personally than I already have in 4e, so I somewhat doubt I’ll be getting many, if any, of the books.

      I also agree that 4e can have a very strong combat/non-combat divide, but while that can be jarring to get used to, 4e’s entire setup is so darn nicely balanced (not perfectly balanced, but there was an attempt, and a good one at that) that I really don’t mind if it feels a bit like a Pokemon game (Walking around, your character’s attacks are almost never explicitly usable, sorta like HMs, but then when you encounter a baddie, roll initiative and play the battle music).

      I think 3.x and Pathfinder have far less of a binary combat division in terms of gameplay, but the balance is such (Especially with the still-persistent problem of linear fighter/quadratic wizard) that it keeps me from really being able to enjoy the system in most of the games I’ve played with them.

      For exploding dice in a wargame, I think as long as it’s appropriate in frequency then I don’t have a problem with it. For example, in Warhammer 40K, it drives me up a wall that S3 or less can *never* injure a AV 10 vehicle, and that nothing short of S8 can ever hurt AV 14. However, the Wrong Way To Do It for exploding dice on vehicle damage (imo) would be to just say “Oh, well if you roll a 6 on Armor Penetration, roll another die and add that to the armor value as well,” since this means you’d be penning AV 14 1/36 of the time at a minimum with S3, and likely even more frequently.

      But I think a system like “If you roll a 6, increase your Armor Pen result by 1 and roll another die. If it is also a 6, increase the Armor Pen by 1 and roll another die, continuing until you fail to roll a 6.” Now, the chance of S3 penning AV 14 is >0, but it is an insanely small fraction and likely to not come up in 99 of 100 games played. But there’s the once-in-a-blue-moon possibility, which I think is important in games with otherwise literally-impossible-to-defeat enemies in certain matchups. With this rule, killing off the last of my S4+ heavy weapons in an IG squad doesn’t mean I basically have to flee whatever vehicle comes at me, but rather I can hope beyond hope that the long odds favor me and I can roll enough to pen a Land Raider with my lasgun (A 2.14E-5 chance, but still a chance!)

  2. I feel to gain the effect you are after from what you described above you would be better suited via the inclusion of a critical hit based system. Now I am actually on the opposite side of the fence, by which I mean by and large I like it when rules enforce a policy where if an attack is too weak or a shot to difficult you cannot succeed.

    On the other hand if general consensus was for a system that allowed for such I like the Dnd style system where in if you score the highest result on a hit you can score a critical if you can confirm said hit by rolling another die and scoring a hit again (any hit mind not just a critical one) this if confirmed could allow you to score damage on a target that you would not otherwise be able (a glancing strike against a vehicle or a auto wound against a T7 critter when you have str3 for example) to or hit a target beyond your skill to hit, but the odds of doing so are incredibly low for basic troopers.

    On the other hand the odds of turning an easy hit into a critical would be far far easier, which I feel is right. Obviously its purely down to a subjective preference but I feel this form of causing damage against a target that you cannot normally harm is far less luck based and will be far more useful to those who have the skill to get critical results and thus deserve a chance to strike a point of weakness upon the target.

  3. Normally I would be all for a critical-hit system, but I’ve played Mordheim quite a bit, and while it’s a blast and a half to play, you can get *very* swingy combat results when you get a critical effect on a roll of 6 to-wound. I think critical effects are best restricted to larger die-sizes for the purpose of probability (1/20 for D&D feels fine to me. Occurs enough that you don’t have the problem of it “never happening,” but also doesn’t happen close to 16% of the time you roll either).

    The biggest reason I don’t like confirming criticals (And why I like that D&D 4e removed that step) it that it slows the game down imo. The confirming crits is a good idea, both logically and to help make sure it’s an event slanted towards players and units more able to damage their foes (Mordheim has a somewhat similar thing, in that if a model needs a 6 to-wound, a roll of 6 doesn’t cause a crit), but the time sink it would result in, especially in a wargame, would be a bit too much (This is just a gut instinct, though, as I haven’t had a chance to try and play with this rule yet).

    • I must admit I was considering it in terms of a Skirmish system rather than a full wargame mainly because that is where my current design focus lies. I feel in a Skirmish system the time concerns you have should not really exist.

      On the other hand I am of the mindset that for a mass combat wargame you really should not need any form of auto damage in place as your army should have the appropriate models to deal with all threats and if you are using your guardsmen to attack land raiders then the issue is more yours than any weakness of system design. Now if a Army list allows for completely unbalanced builds that are not possible to counter for normal armies (for example – armour 14 on all dedicated transports) then its a balance issue and a bad codex release. Further more I feel that a good system will have alternative victory conditions beyond kill the enemy, so that it is by no means essential for any force to be able to wipe to opponent out. I feel it is a combination of these factors that makes me feel in a Wargame especially any exploding dice style system is simply a way of balancing a weakness in design/balance.

      • Iagree that there shouldn’t be an auto-damage system in a wargame (Short of stuff like Apocalypse weapons that are Strength D, which you usually pay through the nose for). However, i do really think you’re not hurting the game by giving any unit a chance against any other, as long as that chance is vanishingly small. The proposed “Each roll of 6 means +1 AV” isn’t meant to make a rank-and-file trooper be an effective replacement for a lascannon or krak missile, but rather give them a very, very, very small chance of being able to hurt a larger model.

        A 3.5*10^-6 chance (Less than 1-in-a-million, btw) of a Guardsman penning a Land Raider does not make the Guardsman an effective replacement for a Lascannon or Heavy Weapons Team in any way, shape, or form (So army lists will be unchanged), but it does mean that if all hope is lost, you can lob your volley of lasgun fire at the Land Raider sitting on your objective or what have you and have a very-very-very-very small chance of hurting it.

        And if you happen to make a 6 roll on the damage chart and blow it up, well that is what we call forging a narrative.

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