With the possible exception of combat-related tests, I suspect that perception-type tests are the most common skill tests in RPGs: What do the characters see and when do they see it?

Despite their ubiquity – or perhaps because of it – perception-type tests are surprisingly challenging for many GMs, and the art of their use can be surprisingly contentious, with those choosing to resolve them in one fashion often feeling that those who resolve them using different techniques are heretics who are ruining their campaigns. (No joke.)

Let’s take a moment to further refine our field of study. Perception-type tests, broadly speaking, can be broken down into two categories: Active perception tests (determining what the character notices when they are consciously making an effort to observe) and passive perception tests (determining what a character notices reactively and/or while engaged in other activities).

Of the two, active perception tests tend to pose little challenge or oddity: The player states their intention and method, and then the action is resolved. There may be some fiddling about with hidden vs. open stakes and difficulty numbers, but these tests are fundamentally resolved like most other tasks.

When it comes to passive perception tests, however, things get more complicated, primarily because such checks inherently create significant metagame knowledge (i.e., knowledge that the player possesses which their character does not): The test, after all, is being made to determine whether or not the character is aware of something. But the mere fact that the test is being made in the first place reveals to the player that there is something the character is (at least potentially) unaware of.

This is problematic because:

• Even if the check is successful, the argument can be made that the significant bifurcation of the player’s experience from the character’s experience is non-optimal.
• It deadens the sense of surprise. (A jump scare is less effective if you know it’s coming.)
• It lets players to abuse their metagame knowledge, allowing them to take actions based on the fact that the test was made.
• Even if the player attempts to avoid such abuse, the mere presence of the knowledge can complicate the decision-making process, filling it with an extra burden of doubt and self-analysis. (For example, maybe you would have been extra cautious about that door up ahead even if you weren’t aware that the GM called for a perception test as soon as you saw it… but are you sure? And even if you’re sure, what will your fellow players think of your choices?)

In order to avoid this cluster of problems created by the metagame knowledge of the passive perception test’s existence, GMs have adopted a variety of special procedures for such tests. Let’s take a moment to briefly discuss the major approaches.

THE PLAYER ROLLS

The first approach, of course, is to just resolve passive perception tests by having the player roll them.

PROS: This is usually the way that other skill tests are resolved, so you’re simply being consistent with your methodology.

CONS: The metagame knowledge we just discussed.

THE GM ROLLS

Okay, simple solution: The GM rolls the test in secret.

PROS: The player doesn’t know the test is being made, so there is no metagame knowledge being imparted.

CONS: The GM has to track the pertinent skill ratings for the PCs. This can be difficult to do accurately, particularly if the system features a lot of different perception-type skills or has lots of buffs, equipment, and/or transient character abilities that cause the perception-type skill bonuses to shift around. In many systems it can actually be impossible to do this, as the players will have optional resources or limited use abilities that could affect the outcome of the check.

And even if the GM does execute the checks without error, players tend to have a greater confidence in checks they rolled themselves. “Whaddya mean we got ambushed? Don’t I get a Spot check? Did you remember that I get a +3 versus spotting cyborgs?”

There is also an inherent time cost (one guy making five checks generally takes longer than five people each making a single test) and a potential pacing problem (players actively resolving something are engaged; players waiting for the GM to finish rolling dice behind their screen are not engaged).

VS. STATIC VALUE

Instead of rolling passive perception tests, the PCs’ passive perception is boiled down to a static score which is compared, without a randomizer, to the difficulty of the test.

PROS: This eliminates some of the problems with the GM rolling. Instead of a time cost, this method can actually result in a time savings, which also means that the pacing problems generally don’t crop up.

CONS: Many of the problems, however, remain (such as keeping track of the PCs’ skill ratings).

More importantly, in practice this method effectively turns passive perception tests into pure GM fiat: The GM will obviously quickly learn what the highest passive perception score is in their group, and when they set the target number for a passive perception test they are ultimately just deciding whether it’s higher or lower than the party’s score. There’s nothing inherently wrong with the spectrum of GM fiat, per se, but what you end up with here is this sort of fake mechanic and a bunch of extra bookkeeping which seems to have no real purpose except to camouflage the fiat. If this is the approach you want to take, it seems to me that you’d be better off skipping all the hassle and just embracing the fiat directly.

UNCERTAIN TASKS

As discussed in The Art of Rulings, you could also adopt the uncertain task method described in Traveller 2300. In this method, both the GM and player resolve the test separately, and the combination of those outcomes results in either no truth, some truth, or total truth.

PROS: The method obscures some of the metagame knowledge imparted when the player makes the roll (i.e., they can’t intuit reliably based off their knowledge of what their die roll was). The GM also doesn’t need to track the PCs’ perception scores, because they can just ask for that information as the check happens.

CONS: This resolution method is more time consuming, particularly when you’re dealing with a scenario where everyone in the group is making the passive perception test. Muddling out five different test result comparisons can be laborsome by itself, but the spectrum of potential results can also create a great deal of confusion when different characters getting different results simultaneously. (Maybe you could have everyone roll and then only resolve the uncertain task comparison check with the character who rolled best to determine what the group actually observes?)

Go to Part 2: The Perception Tapestry

Go to Part 1

True rituals are very complicated spells that are the stuff of legend. They are far beyond the power of any single spellcaster and can only be cast in ritual form. They cannot by further augmented by any feats or other abilities. True rituals combine all aspects of magic and have no schools of magic associated with them.

True rituals are cast as normal spells with the exceptions detailed below.

TRUE RITUAL COMPONENTS

All true rituals have verbal, somatic, material, and experience cost components. Each member of the ritual must pay the experience cost. If the ritual is using proxy ritual members to cast the spell (see below), the experience cost of the replace caster(s) is divided equally among the normal casters who are participating in the true ritual. If the experience cost lowers one of the caster’s levels, the lost level must come from the caster’s primary spellcaster class.

CASTERS REQUIRED

Each true ritual has a minimum number of required casters. Each caster must have the spell prepared in the usual fashion at the time of casting. True rituals are prepared in lieu of one of the caster’s spells of equivalent level.

With multiple casters, the power of the ritual is increased. Use the level of the highest caster in the group and add the number of other casters (not proxies) participating in the true ritual to determine the effective caster level. The ritual’s effects are based upon this effective caster level.

PROXIES

Some true rituals allow a proxy in place of one or more of the required casters. The proxy section of a true ritual details who can replace a required caster during the ritual. Proxies cannot replace every caster: There must be at least one spellcaster to lead the ritual.

SAVING THROW

True rituals have more power behind them, which in turn makes them more difficult to resist. Any saving throw against a true ritual has a DC of 15 + the level of the spell + the relevant ability modifier of the highest-level caster participating in the ritual.

COUNTERING RITUAL MAGIC

Dispelling or countering augmented and combined ritual castings of a spell is similar to countering a normal casting of the spell. Of course, the longer casting time offers a larger window of opportunity to disrupt the spell. Throughout the casting, observers get a Spellcraft check (DC 18 + the spell’s level). The DC is slightly higher due to the changes in the prolonged casting, but the longer casting time allows for a retry of the check each round. Using dispel magic to counter an augmented or combined ritual casting is much easier due to the delicate and extended manipulation of the magical energies involved. The dispel check goes against a DC of 6 + the spell’s caster level if the dispel check is made during the casting of the ritual spell.

As with countering metamagic feats, any additional effects or added levels are not taken into account when counterspelling a ritual casting. A regular cone of cold spell counters a ritually enhanced cone of cold.

True rituals cannot be countered with knowledge of the true ritual in question: The preparations are too long and complicated to enact even throughout the hours of casting time required. True rituals can easily be disrupted, however, through combat, distraction, or other means. Unlike augmented or combined ritual castings, any dispel magic checks to counterspell a true ritual go against a DC of 15 + the caster level of the true ritual’s highest-level caster.

RESEARCHING ORIGINAL TRUE RITUALS

Any spellcaster who can cast a true ritual can attempt to create a new, original true ritual. Creating a true ritual, however, is much more demanding than creating a normal spell.

Like the research of a regular spell, the creation of a true ritual requires access to a well-stocked library for a wizard and meditation, prayer, and sacrifices in a major temple or blessed location for clerics and druids. A wizard’s library must be comprised of books, treatises, and manuscripts totaling at least 50,000 gp in value. Magical items and spellbooks do not count toward this total for the personal library’s value.

The research must be conducted by at least three spellcasters of the same type  (arcane or divine) who collaborate on the ritual’s research. During the research, each of the spellcasters must pay 1,000 gp per week with a minimum of one week per effective level of the true ritual. This money goes into the same fees, experimentation, and components that regular spell research consumes. At the end of the research period, each of the researchers makes a Spellcraft check against a DC of 20 + the spell level. If all the researchers succeed, the new true ritual has been successfully created (assuming the spell is viable). If any of the researchers fail, however, they must all go through the research process again if they wish to keep attempting to learn the true ritual.

The criteria for a viable true ritual are entirely dependent upon the requirements of the DM. Use the guidelines for new spell creations found in the core rulebooks. Compare any new true ritual concept with those presented in this chapter.

The following elements are required for all true rituals:

• A minimum of three casters is required to perform a true ritual. More may be required depending on the ritual.
• The ritual must have an experience point cost to cast. Higher experience point costs can balance the power level of some true rituals.
• The number of casters required to cast a true ritual is also the number of casters that are required to research the ritual. Requiring a higher number of creators can also serve to balance the ritual’s power level, though not as much as an experience point cost (and not if the PCs acquire the ritual through means other than research).

This material is covered by the Open Gaming License.

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Under the direction of a single spellcaster, a group of individuals can work together to generate greater spell effects. Similar to the use of augmented ritual casting, the primary caster uses ritual casting to enhance the basic prepared spell (or a free spell slot for a bard or sorcerer). Although groups with like magic (divine or arcane) work best together, anyone can assist with the performance of the ritual (although the lack of precision by non-spellcasters adds to the chance of failure).

Combined ritual casting works differently than augmented ritual casting: The caster and participants do not need to have an understanding of metamagic feats. Instead, the leader of the combined ritual casts the spell to be modified, and the auxiliary members of the ritual contribute their will, desire, and life energies to supplement the overall power of the spell.

This supplementary power is used as bonus levels that are split between the different aspects of the spell. Each aspect of a spell that varies with caster level (range, number of targets, area, duration, damage dice, etc.) is treated as a separate category that can be increased with bonus levels generated by the combined ritual casting. The supplementary bonus levels provided by the ritual casting cannot violate the restrictions or limits of the spell. For example, a combined ritual casting of fireball cannot exceed the spell’s 10-die maximum for damage.

The leader (who casts the actual spell) uses their caster level as the starting level in each category of the casting. The total bonus levels, as shown on the table, are then divided up and added into each category as the primary caster chooses. The caster’s level plus the extra bonus levels now determine the effects for each of the spell’s separate categories.

Add all partial levels and round down to determine the total bonus levels added to the spell. Add an additional +1 bonus level per participant that has the ability to cast the spell in question, reflecting the added spell knowledge and caster level ability. (Crossover between arcane and divine versions of the same spells are permissible for this bonus.)

COMBINED RITUAL CASTING TIME

The casting time of a combined ritual casting is the base time of the ritual casting (as shown on the table below) multiplied by the number of participants and the spell level:

(base ritual time) x (# of participants) x (spell level)

The number of participants does not include the leader of the combined ritual, only the people who are helping to power the spell.

Any casting time of an hour or longer requires the leader to make a Ritual Casting check at a DC of 10 + the spell level. The DC of this check is increased by one for every non-spellcaster participating in the ritual. If this check is failed, the energies involved with the combined ritual casting create a backlash that affects all of the participants, resulting in (ritual bonus levels x spell level) hp of damage. A successful Will throw (DC 15 + spell level) reduces this damage by half. The combined ritual is still cast in the event of a failed Ritual Casting check, but only half of the supplementary bonus levels can be harnessed prior to the spell discharge.

COMBINED RITUAL MATERIAL COMPONENTS

Combined ritual casting also requires expensive material components. These additional components are similar to those used in augmented ritual casting and represent the same types of ingredients. The cost of the material components is a number of gold pieces equal to:

10 gp x (# of participants) x (spell level)

Go to Ritual Casting – Part 3: True Rituals