If you’re walking in on the middle of the Advanced Fantasy Dungeon series, there’s an index here.

Surprise and ambush are simple in second edition, so general principles:

• If either anyone encounters someone else unexpectedly, they roll for surprise.
• The surprised group has disadvantage on defence.
• The unsurprised group has advantage on fleeing and attacks, and gets a free round of attacks with weapons but not spells. If they planned an ambush, they get spells too.
• Chance of being surprised is 30% and is higher if you are fleeing, in darkness or twilight, panicked, en mass or smell.
• Your opponent is more likely to be surprised if you are silenced, invisible, anticipating attack or suspicious.

The challenge now is to simplify this and utilise existing mechanics. Firstly, we need surprise to be not a d10 roll. Secondly, it’s better to have one roll for PCs, not one for each side. Thirdly, simplifying the penalties is essential.

If you might be surprised, make a group dexterity check.

If you are carrying light, fleeing, in twilight or equivalent, panicked, en mass or malodorous, or if the opposing party is carrying light, sneaking, anticipating attack, suspicious, or anticipating violence you have disadvantage. These things cancel out.

If you are cannot see or fleeing, or the opposing party is invisible or magically silenced, you are surprised. If you are invisible or magically silenced, or the other party cannot see or fleeing, they are surprised. These things cancel out.

If a member of your party has a special ability that opposes your enemies’ advantages, for example infravision, you gain +1 to your check for each advantage.

If you are surprised, the opposing party takes an free attack against you without using spells, and you have disadvantage on saving throws for that round, or can flee before you react. If they planned an ambush, they may use spells.

If you surprise them, you take a free attack against them without using spells, you have +5 to your first attack, or you can flee before you react. If you planned an ambush, you may use spells.

There, sorted, note for note. This adds something that we need to back track on for ability checks: We need group check rules! I’ll have to revise that again next. Because of the one-sided roll, this is more wordy than I’d like with too much repetition, so I’ll try to fix that.

If you might be surprised, make a single surprise check for your group. The target for a surprise check is 14.

If you are carrying light, fleeing or en mass, or if the opposing party can see you, is sneaking, or is suspicious you have disadvantage.

If you cannot see or are fleeing, or the opposing party is invisible or magically silenced, you are surprised without a roll. If you cannot see or are fleeing, or the opposing party is invisible or magically silenced, you have advantage.

If your party is surprised but a member of your party is able to head off any of your disadvantages, for example by having infravision, they make their own check individually, and may not be surprised.

The unsurprised party takes an free attack against the surprised party without using spells, and they have +5 to attacks (or the surprised have disadvantage on saving throws) that round, or they can flee before you react. If they planned an ambush, they may use spells.

This has been a part of the Advanced Fantasy Dungeon Series! Let me know your thoughts on surprise, particularly if I can simplify this rule — I am certain I can! Are there glaring questions left unanswered, or have I overlooked anything important, or is all of this a waste of time!

Idle Cartulary

17th April 2022