Version 0.96 (2025-04-24)
This chapter introduces the core mechanics of the Shadowrun:
2097 game system.
Two types of dice are used: 2d10 are used to determine success or failure, and a number
of d6s are used to determine variable damage and initiative.
The Success Check section outlines setting Target
Numbers (TN), calculating skill bonuses, and rolling dice to determine success
or failure for skill checks, attacks, and other endeavors. This is further
expanded upon by explaining how Advantage/Disadvantage, Margin of Success
(MoS), and Rolling Doubles interact with how success or failure is
determined.
Mechanics for Variable Damage Rolls and the Armor System
explain how you do damage—and
how armor can stop or reduce that damage.
Finally, the Edge system is detailed, providing ways
for players to influence rolls, manipulate initiative, boost damage, survive
otherwise fatal blows, and even avoid outright death with the costly Edge
Burn mechanic.
Success
checks
The game’s mechanic for resolving skill checks, attack
rolls, and more is the Success Check (SC):
1.
Determine Target Number (TN)
2.
Determine Advantage/Disadvantage
3.
Roll 2d10 (3d10 if Advantage/Disadvantage)
4.
Add Skill Bonus (skill ranks + 2
governing attributes)
5.
Success if dice and skill bonus ≥ TN
6.
Margin of Success (MoS) is equal to the result
minus TN.
1. Determine the Target Number (TN)
The GM sets a Target Number based on the difficulty of the
task. TN values typically range from 15 to 30, though higher TNs are possible
for exceptionally difficult tasks. TNs lower than 15 are rarely used; anything
that easy is probably not worth making a check for—unless the character has a
low chance of success and the task is of dramatic importance.
2. Determine Advantage and Disadvantage
Determine if you have Advantage or Disadvantage on the check.
·
Advantage: Advantage can be granted by
favorable conditions, gear, or character talents. Another way to gain Advantage
is by spending a point of Edge (see below).
·
Disadvantage: Disadvantage can be imposed
due to unfavorable conditions, lack of proper gear, or powerful adversaries.
Using Edge in conjunction with Advantage/disadvantage:
·
Edge can be spent during this step to gain
Advantage if you do not already have it or to remove Disadvantage, but you cannot
do both for the same check.
3. Roll Dice
Roll 2d10 and add the results together.
·
With Advantage: Roll 3d10, then remove
one die of your choice (usually the lowest result, but there are exceptions) before
adding the results together.
·
With Disadvantage: Roll 3d10, then remove
one die chosen by the GM (usually the higest result, but there are exceptions)
before adding the results together.
4. Add the Skill Bonus (SB)
Identify the relevant skill for the task, then add your Skill
Bonus (SB) to the dice roll.
Calculating the skill bonus:
·
Skill Ranks: Add the character’s ranks in
the skill being used.
·
Key Attributes: Combine the values of the
two key attributes for the skill.
5. Determine Success or Failure
If the total meets or exceeds the TN, the check is
successful. Otherwise, it is a failure.
6. Magnitude of Success/Failure (MoS)
Some checks may require only a simple success or failure,
but for many checks, how well you succeeded (or how badly you failed) is
essential.
Calculate Margin of Success (MoS): The Margin of
Success is the total from the SC minus the TN. MoS indicates how well the check
was performed.
·
Positive MoS:
o 0
to 4: Marginal (but still a success).
o 5
to 9: Significant Success.
§
Attack: Add 1d6 to your damage pool.
§
Non-attack: At the GM’s discretion, gain
Advantage on your next related SC.
o
10 or more: Complete success.
§
Attack: Add 2d6 to your damage pool.
§
Non-attack: At the GM’s discretion, gain
Advantage on your next SC (even if unrelated). Alternatively, the GM might
offer another benefit.
·
Negative MoS:
o
-1 to -5: Marginal failure.
o
-6 to -10: Significant failure. You gain
Disadvantage on your next related SC.
o
Below -10: Complete failure. You gain
Disadvantage on your next SC and additional penalties at the GM’s discretion.
Rolling Double
Rolling doubles amplifies success and failure. For this
reason, you might want to keep a double instead of the highest number when
rolling with Advantage. For the same reason, the GM might tell you to remove a
lower number if that leaves you with a double—and he knows you’ll fail even
more spectacularly.
·
If You Succeed: If you rolled a double
and succeeded, add 5 to your Margin of Success (MoS). This represents an
extraordinary performance.
·
If You Failed: If you rolled a double and
failed, subtract 5 from your Margin of Failure. This represents a significant
mishap.
·
If You Used Edge: Always add 5 to your
MoS, even if you would fail the check. This might make you succeed after all—or
reduce the severity of your failure.
Understanding the probability curve of 2d10
Rolling 2d10
creates a bell-shaped probability distribution. Unlike a single d20 or d100,
2d10 clusters results around the middle, making mid-range results more common.
Probability
breakdown for 2d10:
1.
Probability
of Rolling 5 or Higher:
Approximately 94% (compared to 80% for 1d20)
2.
Probability
of Rolling 10 or Higher:
Approximately 64% (compared to 55% for 1d20)
3.
Probability
of Rolling 15 or Higher:
Approximately 21% (compared to 30% for 1d20)
4.
Probability
of Rolling 20:
Approximately 1% (compared to 5% for 1d20)
This distribution
helps design challenges with a predictable range of results, allowing for a
balance between variability and success. The rules for Advantage/Disadvantage,
Edge, and rolling doubles add another layer of complexity and depth to the
equation.
Difficulty levels
Some challenges
and tasks may be assigned intermediate TNs. For example, if something is
slightly more complex than Moderate but not quite Challenging, a TN of 22 could
be appropriate.
If the difficulty
level is pretty obvious, like a check being Very Difficult (i.e., beyond what
most people can achieve), the GM should just say “Very Difficult”, and the
players should interpret that as “around 35”. The GM may hint (or straight-up
lie) if the difficulty is less apparent—or just not tell you the difficulty at
all.
Moderate
difficulty has a TN of 20. Assuming a +15 skill bonus, a professional in the
field should succeed approximately 95% of the time, while a less skilled but
still trained person (+10 skill bonus) will get it right about 2/3 of the time.
The same professional would have a 2/3 chance of succeeding at a TN 25 task,
but this would drop dramatically to 1/5 for a TN 30 check. Using Advantage,
they could significantly increase their chances of success, and if able to
spend Edge, could further improve their chances.
Most checks will
be in the 15-30 range, but knowing players, they are likely to try stuff
that’s, if not downright impossible, then close to it. There is no hard upper
limit for TNs, but anything above 40 is virtually impossible for all but the
most epic of characters. If a task is quite literally impossible, such as a
normal person flapping their arms to fly, then the task cannot even be
attempted. Don’t bother rolling the dice—it’s an auto-fail.
10 (Very Easy)
This task is straightforward and requires minimal effort.
Most people, even without specialized training, should be able to accomplish it
easily. It’s typically not worth rolling unless you’re under significant
pressure or have Disadvantage in conjunction with a low skill modifier.
15 (Easy)
A task that might require some attention but is well within
the capabilities of most people with a basic understanding or some relevant
experience.
20 (Moderate – Default)
The standard difficulty for tasks that present a challenge
but should be manageable for someone with relevant skills or experience. A
professional in the field should succeed most of the time.
25 (Challenging)
A more difficult task requiring a higher level of skill or
expertise. Success is not guaranteed, even for a professional, and may require
some level of preparation or focus.
30 (Difficult)
A task requiring significant skill or expertise. Only those
highly trained or experienced can regularly succeed.
35 (Very Difficult)
A challenge only the most skilled individuals can achieve.
Even for experts, success is far from guaranteed.
40+ (Near Impossible)
A task almost beyond the reach of even the most skilled
experts. Success requires exceptional skill, luck, perfect conditions, or
extraordinary effort. Failure is highly likely.
Advantage/Disadvantage
While some
situations may apply flat bonuses or penalties to success checks (usually when
your skill is directly impacted rather than the circumstances of the check),
the system more commonly utilizes the Advantage/Disadvantage mechanic to
represent dynamic changes in a situation.
·
Advantage means you roll an extra die (3d10 instead
of 2d10) and then remove a die of your choice.
o You will usually want to remove the lowest roll,
but sometimes, you might want to remove another result to get a double.
·
Disadvantage means you roll 3d10 and then remove a
die of the GM’s choice.
o You will usually have to remove the highest
roll, but sometimes, you might be forced to remove another result to force a
double.
How Advantage
and Disadvantage Affect Rolls
·
Advantage and Disadvantage are roughly
equivalent to a +2.5 or -2.5 modifier on your success check
(discounting the effects of rolling doubles) but do not affect the maximum or
minimum you can roll.
Multiple
sources of Advantage/Disadvantage
You either have
Advantage, or you don’t. The same goes for Disadvantage.
·
There
is no stacking of Advantage/Disadvantage even if you have multiple sources of
either.
·
If you
have BOTH Advantage and Disadvantage on the same check, you have neither.
Removing
Advantage/Disadvantage
Some game effects
may call for removing Advantage or Disadvantage from a check. This is
NOT the same as giving Advantage or Disadvantage.
For example, night
vision goggles remove Disadvantage from combat checks (among other things) made
in low-light conditions, which means you can now gain Advantage from another
source without having it canceled.
Using Edge with
Advantage/Disadvantage
If you spent Edge
to gain Advantage or remove Disadvantage, there is an added benefit:
·
Any
double will increase MoS by 5, even if the check would normally result in a
failure (and thus -5 MoS).
Variable damage rolls
Damage, whether
from weapons, spells, or environmental effects, is determined by rolling a
number of d6 and adding a modifier based on the weapon’s Strength
attribute (melee weapons use the wielder’s Strength, ranged weapons use their
own).
Examples:
1.
Street
Samurai: ST 6 attacks a
thug with a sword, doing 2d6+6 damage (2d6 for the sword, +6 for ST). If MoS
had been +10 or greater, 4d6+6 would have been rolled instead.
2.
Guard: Shoots a runner with a burst from his SMG,
doing 3d6+4 damage (2d6 base for the SMG, +1d6 from burst, +4 for the weapon’s
ST).
The bell curve
created by multiple d6 rolls means that the more dice rolled, the more likely
you will get average results. This system provides consistency in damage while
still allowing for extreme highs and lows.
Weapon
examples:
While the
Equipment chapter has all the details, it’s worth mentioning that for firearms,
2d6+4 is considered the "standard" damage of a light firearm, such as
a light pistol or Ingram Smartgun (ignoring the burst and smart-gun features
for now), heavy pistols (such as the Ares Predator) does 3d6+5 damage, 4d6+6 is
assault rifle damage, 6d6+8 is a typical sniper rifle, while your trusted
assault cannon does 8d6+10 damage.
Melee damage is
less varied, with 2d6+ST being the standard damage for many weapons, but a
troll attacking you with a two-handed fractal-serrated glaive will do a lot
more damage than that. Punching someone with the intent to harm them does
1d6+ST Stun damage, which is kind of dangerous but not as terrible as
being stabbed or shot.
Magic spells, Matrix
combat, environmental hazards, and vehicle combat follow a similar pattern but
with unique quirks, so once you learn the base system, you’re well-equipped to
handle more exotic forms of combat.
Damage mitigation (armor)
If you get hit,
you will suffer damage. Armor can help mitigate damage entirely or partially.
All forms of armor (physical, magical, Matrix, etc.) are rated for Penetration
Threshold (PT) and Damage Reduction (DR).
·
Damage
below the PT is entirely negated (although the armor itself can become
degraded).
·
Damage
that’s at least equal to PT has penetrated but is reduced as follows:
o Penetrating damage is reduced by the armor
DR as a percentage.
Example:
Pistol vs. Light
Armor: 2d6+4 vs. PT 15/DR 30.
The attacker must roll at least 15 damage, so he needs 11 total on 2d6 to
penetrate. Anything less is entirely stopped by the armor. But for the sake of
argument, let’s say he rolled a 12, so 16 total. The armor soaks 30% of that,
or 4 points, leaving 12 damage.
This is a straightforward
example of using a semi-auto pistol against light armor protection. If the
shooter got a high MoS, he’d get extra dice, burst fire does more damage, there
are special ammo types, etc. If the defender had more serious armor protection
(assault armor PT35/DR60), the attacker would need a much more powerful weapon
to penetrate. This and much more are covered in relevant chapters (combat,
equipment, magic, etc.).
As a rule of
thumb, light armor is PT15/DR20, medium armor is PT25/DR40, and heavy armor is
PT35/DR60, but there is considerable variation between armor types and models.
Anything heavier than light armor will slow the wearer and reduce their Dodge
defense.
All armor follows
the same general rules, be it manufactured armor, natural armor, magical armor,
Matrix armor, vehicle armor, or whatever.
Edge
Edge is a fluid and powerful resource that
players can use to influence the outcome of rolls, increase damage, and avoid
catastrophic injuries. It’s designed to be spent frequently, with the knowledge
that it can be regained through rest, success, or even failure.
Using Edge
1.
Gain
or Remove Advantage/Disadvantage:
·
Gain
Advantage: Spend 1 Edge to
roll 3d10 and choose which die to remove.
·
Remove
Disadvantage: Spend 1 Edge
to negate Disadvantage and roll 2d10 normally.
When using Edge in
this manner, any double adds 5 to the total (instead of subtracting 5 if
it would otherwise be a failure. Thus, a double could potentially transform a
failure into a success.
2.
Improve
Initiative:
·
Boost
Initiative: Spend 1 Edge
to boost your initiative by +2d6 for one turn.
3.
Boost
Damage:
·
Boost
damage: Spend 1 Edge to
roll +2d6 when determining variable damage.
4.
Reduce
Injury Severity:
·
Lessen
Injury: Spend 1 Edge to
reduce the severity of an injury by 1 step. This can prevent a serious injury
from becoming critical or life-threatening or turn an inconvenient moderate
injury into a grazing blow.
Edge Recovery
Edge is designed to be a fluid resource,
encouraging players to spend it freely, knowing it can be regained through rest
or during gameplay.
·
Long
Rest: Regain 1 Edge point.
·
Between
scenarios (not sessions):
Regain all Edge points.
Edge Regained
During Play
In addition to
rest, players can regain Edge based on their actions, achievements, and
setbacks. The ease with which Edge is regained is influenced by both the
character’s current Edge and their maximum Edge, plus the magnitude of their
successes (or failures).
1.
Achievements
and Success:
·
Characters
regain Edge after achieving significant objectives, such as reaching key
milestones, completing missions, defeating major enemies (bosses), or coming up
with clever solutions.
Example: Overcoming
a major obstacle or defeating a powerful (boss) enemy might restore 1 Edge (or
more for characters with low current Edge and high max Edge). Taking down the
Big Bad will restore Edge to its maximum value for everyone.
2.
Failures
and Setbacks:
·
Edge can
also be regained when the team faces significant failures or setbacks,
reflecting the characters’ resilience in the face of adversity.
Example: Coming up
with a good plan that, for whatever reason, fails might restore some
Edge as the characters grit their teeth in the face of adversity. No Edge is
restored if the plan was stupid or never likely to succeed in the first place.
Edge Burn
Edge Burn is a last-resort mechanic used to prevent
a character’s death. By permanently sacrificing a portion of their Edge,
a character can avoid immediate death but still require urgent medical
attention and a lengthy recovery period.
·
Effects
of Edge Burn:
o Avoids outright death but needs immediate
medical attention and long-term recovery.
o Cost: Edge Burn reduces the character’s current Edge by 1 and permanently
reduces their maximum Edge score by 1. This means they can no longer regain
that point of Edge, limiting how often they can use this feature.
o Restrictions: Edge Burn is only used to prevent outright
death—it cannot be used to avoid other forms of harm or failure. For example,
if a troll rips off your arm and beats you to death with it, you will somehow
survive long enough to be brought to the ER, but the arm still needs to be
reattached, regrown, or replaced.
This mechanic
provides players with a safety net in extreme situations, but at a cost that
grows heavier over time, ensuring that Edge Burn is only used in truly
life-or-death moments.
No comments:
Post a Comment