Coming soon, a handbook all about opposed checks. How to win them. How to cause them. How to calculate the damn math correctly.
This will be more of an analysis of the mechanics than a usual guide to making it perfect. There will be some of that, but opposed checks are a broad enough mechanic that trying to cover everything is far more than one guide should have. Most of this will be math and analysis, but there will also be some about general techniques to boost the more common types of opposed checks and a few more specific, interesting or obscure things.
Really, the main reason I'm making this is for the math to be readily available for anyone that wants it.Things that use opposed checks
Disarm/Sunder: Opposed attack rolls. +4 bonus for two-handed weapons, -4 penalty for light weapons. Also another +4 per size category difference to the larger opponent.
Bull Rush/Overrun/Trip: Opposed Strength checks. +4 bonus for each size category above Medium, -4 for each one below. Defender can oppose your Strength with Dexterity instead for trips.
Grapple: Opposed grapple checks. Uses BaB + Strength, with a +4 bonus for each size category above Medium, -4 for each one below. Too many options makes this a pain to follow, especially when they aren't even consistent on what actions they use.
Bluff: Opposed by Sense Motive for telling lies. Opposed by the sum on Sense Motive and BaB for feinting, so it really sucks against anyone with a few ranks in the skill and a good BaB, not to mention that feinting is usually unimpressive unless you have something really special.
Diplomacy: Mostly uses flat DCs, but arguing against someone is an opposed check. Useful to protect against Diplomancers.
Disguise: Opposed by Spot. Really easy to boost with shapechanging magic.
Escape Artist: Can be opposed by someone else's Use Rope check if you're tied up and trying to escape. One of the few cases where you can take 20 on an opposed check. Since the Use Rope check is amde well in advance and persists until the situation chenges, it's almost like rolling against a fixed DC. Note that the rope user gets a +10 bonus, so you'll probably lose on a tie.
Forgery: Forging something can only be detected by an opposed Forgery check. Despite the fact that your check is fixed when you forge the document, opponents cannot retry so they can't take 20.
Hide: Opposed by Spot.
Intimidate: Opposed by a modified level check.
Listen: Opposed by Move Silently.
Move Silently: Opposed by Listen.
Sense Motive: Opposed by Bluff.
Sleight of Hand: Stealing something is a flat DC and an opposed check (vs. Spot) at the same time. Hiding a weapon or object is opposed by Search (or Spot if they see you doing it), and gets various bonuses based on your clothing and the object being hidden.
Spot: Opposed by Disguise or Hide, as appropriate. Occasionally opposed by Sleight of Hand, but only to notice it, not to stop it.
Use Rope: Opposed by Escape Artist to tie soemone up, but you get a massive +10 bonus. On the other hand, they can take 20.
Initiaitve: Not technically an opposed check, but functions alot like one. Special mention due to its similarity and importance.
Charisma: Special mention due to its use with charm spells and planar binding spells.
Opposed Rank Checks: For deities going up against other deities. This can have significant effects on a victory and there are a few things that specifically affect the way this works. Utterly irrelevant in most games.
Fate Mantle - Add your level in the class that granted you mantles to any d20 roll 1/day.
Competition Domain - Get a +1 bonus on all opposed checks.
Pride Domain - Reroll 1s. Less useful here than elsewhere, but still roughly equivalent to a +0.5 bonus.
Saves only, and I don't think there are any opposed saving throws outside of homebrew.
Luck Domain - Reroll any die 1/day. Always useful.
Rerolls - Always useful, particularly with the variable target number of opposed checks.
Surge of Malevolence - Gives a bonus based on your Depravity/Corruption (don't remember which) once per day. Maxes out at a +9 bonus.
Reroll Wars - Can happen when you and your opponent can both reroll things after determining the result. Whoever has the most rerolls available holds an advantage, but static modifiers count more the more rerolls are involved (and thus the higher average die roll).
Skill Mastery - If you can take 10, it's like your opponent is making a fixed DC check, except that you can still have an advantage on a tie (thus forcing him to beat the "fixed DC" rather than just meet it). You only need a +10 modifier instead of +19 to assure victory this way. Worse than rolling if your relative modifier is +3 or less. Better than rolling if your modifier is +5 or better. Breaks even at a +4 relative modifier (70% success either way). However, taking 10 may prevent you from rerolling, which is a bad thing, especially in reroll wars when taking 10 would only give you a small advantage compared to rolling.
Savvy Rogue - Lets you take 12. Actually, gives you a +2 bonus when you take 10 (which is even better if you've got a relative modifier between -2 and +0). Makes "Taking 12" better than rolling with a relative modifier all the way down to -7 (before including the +2 taking 10 bonus). The difference isn't huge down there, but it's amazing the diference in range of usefulness.Disarm/Sunder
- Unlike PA and Strength bonuses, the +/-4 modifier cares about the kind of weapon, not how you wield it (ie: you get the +4 bonus only if you're actually using a two-handed weapon, not just using a one-handed weapon in two hands).
Rerolling - Rerolling after you know the results is interesting because it makes the opposed check into two parts. The initial roll follows the usual math for opposed checks. The reroll follows the usual math for fixed DCs instead (with the exception of tie breakers), since you know what your opponent's roll is.