Rules Clarification: Surprise and Reaction Bonus
The reaction bonus number provided by Dexterity is applied to surprise to negate some or all of the surprise segments granted by the surprise roll. Each point of difference between the opposed sides’ surprise rolls is a segment.
By default, this means that each side rolls a d6 for surprise and the difference is the number of surprise segments. A character with a Dexterity reaction bonus can negate the surprise if that bonus exceeds the die difference. In that case, that one character is not part of combat (i.e., neither attacks nor is attacked) until after initiative in the first normal round.
For combat involving creatures or characters that use other dice or percentages to determine surprise, we will need to roll percentile dice. The article linked below from Dragon Magazine #133 explains how we will resolve these situations.
For example, the Starchie Boyz have a 2-in-6 (33%) chance of being surprised while Chuq is a monk who can be surprised only 30% of the time. Let’s assume the opposing side surprises on the normal 2-in-6 chance. If the party rolls under 29%, Chuq can be surprised if the opposing side rolls 68% or more (5+ segments, minus 2 segments for the party’s roll, minus 2 segments for his reaction bonus which equals 1+ surprise segments). The remainder of the party in this situation would be surprised if the opposing side rolls 34% or more (3+ segments, minus 2 segments for the party’s roll, which equals 1+ surprise segments).
#rules-clarification
I purposefully fudged this last night to keep things going because it was obvious that someone must have worked this out already. A little more complicated than I like, but it mostly makes sense to me.
this is some of that arcane, byzantine, 1st edition “rules expanded upon rules” mystical voodoo that i don’t like so much. how about we just switch to using that % table all the time?
In practice, we will be because Ray’s monk will be part of every encounter.
In other words, you can safely ignore most of the text and first table — we’ll roll percentile dice and use the second chart to determine the number of surprise segments.
Ahh, yes – makes sense but I think what is just as relevant to our ‘surprise’ encounter is a little bit I just ready on page 61 of the DMG. 2nd paragraph under Surprise heading: “Surprise is determined by rolling a six-sided die for each party concerned, modifying the result by using the most favorable (favourable for Anthony) member of the party concerned, i.e. a ranger, surprised only on a roll of 1, will represent the whole of a group of other character types.
So it seems Chuq shouldn’t have rolled his own surprise and the whole group with him will be using percentage dice from now on (unless you rule otherwise John).
And I was wrong, Chuq CAN be surprised. His DEX reaction bonus is applied to the number of segments he is surprised (5th para, page 62 DMG). If an opposing force causes 1 to 3 segments of surprise to his side, he is surprised for 0 of those segments. If THEY cause four segments of surprise to HIS side, Chuq is surprised for the only the first segment. ETC.
I’ll say it again – we need a ranger. There’s a shit load of XP for Chuq to reach 10th level!
Good catch on the most favorable bit; that simplifies matters. Also, since my house rules only allow one attack during surprise regardless of its length, it only matters if a character’s reaction bonus cancels the number of surprise segments or not (i.e., the effects are the same no matter how many surprise segments). So for Chuq, the only considerations will be: 1) did the group roll less than 30% (or 28%, etc. depending on his level); 2) is the surprise factor difference greater than two segments.
John –
1) from the House Rules 20140103 (most current?) : “AP members can make one attack routine (missile or melee) in each surprise combat round.” Reads much the same in the DMG.
2) surprise factor difference greater than three segments, right? Reaction/Attacking Adjustment for 18 DEX is +3, correct? The penalty applies as well? 3 DEX adds … wait for it …. 4 segments of surprise (that’s what I call a curse)
Segment vs. round — although I will clean up the language to clarify my intent. Really, I’m being kind of soft anyway. My rationale was that the party could win surprise fifty times and it would be great for them under the book rules — however, basic probability guarantees that someday I will crush you and get four segments of surprise with some particularly nasty enemy. Does the party want fifty combats with advantage for one that leads to a TPK before anyone gets to react? One attack for the surprising enemy means the resolution of surprise will cause less swing in combat outcomes in the long run.
Edit: Ah yes, that’s why I had “one” bold-faced in the description of how many attacks during surprise; I’ve changed the language a bit to make this clearer.
Revision: Re-reading the rules, I finally noticed that you only subtract the rolls/factors to determine length of surprise if both parties fail their roll. If only one side fails, they are surprised for the total of their roll/factor regardless of the other sides roll. I will update the house rules document and Roll20 summary accordingly.