Surprise: An Operational Guide

Last Updated: 210815

I’ve written a lot about Surprise recently. There’s a lot of details; I thought I’d provide a brief operational overview (which I’ve retroactively incorporated into in the core Surprise article ) 

    1. Roll Move Silently (where applicable) and other effects that determine Hidden or Silent (such as Boots or Cloak of Elvenkind)
      1. Move Silently provides a Base Surprise modifier you need for the next step
    2. Determine the potential Base Surprise for each involved Party
      1. Normally 2 in 6, this can be modified by Class, Race/Monster, Stealth/Silence, and Invisibility
      2. See for extended details
    3. Roll for Base Surprise for each party (normally 1-2 on a d6)
    4. Determine Encounter Distance
      1. If any party was surprised: d3″ (indoors); 6d4″ modified by terrain – Base Surprise” (outdoors)
      2. If neither party was surprised: d6 +4″ (indoors); 6d4″ (outdoors). Move on to Initiative
      3. Adjust (if necessary) by line-of-sight/ size of room
    5. Determine Surprise duration (in segments)
      1. Surprise duration is the same number that determines if the party was surprised (e.g., a party that rolled a 5 when surprised 1-5 in d6, is surprised, for 5 segments)
      2. If neither party is surprised, move on to Initiative
      3. If both parties are equally surprised, move on to Initiative
      4. If only one party is surprised, Surprise duration for that party is the Base Surprise.
      5. If one party is more surprised, Surprise duration (in segments) for the most surprised party is: (most surprised party’s Base Surprise) – (least surprised party’s Base Surprise). Only one party will be surprised.
    6. Determine individual Surprise duration
      1. Adjust the number of segments each individual in a Surprised party can be affected according to their Dexterity, encumbrance, or other modifiers.
      2. An individual with ≤ 0 Surprise segments remaining will no longer be affected by individual attacks (melee or ranged), but cannot respond in any other way.
    7. Process each Base Surprise segment as a full round in but a single segment (actions 4.A-H).
      1. Movement is 1/10th normal (a single segment)
      2. Casting time is by segment. Any spell not completed in a Surprise segment carries over to the next segment of Surprise, and then carries over into Initiative if still not complete.
      3. Ranged weapons fire at three times the normal rate if ready (in other words, if prior to the first surprise segment: “I’ll nock an arrow”, “Ready weapons and missiles”), otherwise at normal rates (e.g., I read this as three arrows the first segment if nocked and ready, and two arrows for later Surprise segments).
      4. Any individual attack (melee or ranged) against a surprised opponent with no remaining individual surprise segments is deferred to Initiative.
    8. Process extended Surprise
      1. Any individual with remaining Surprise segments can be individually attacked (melee or ranged) for any remaining individual surprise segment. No other actions by attacker(s) are possible.
    9. Roll Initiative
      1. Adjust any spell casting time by whatever arcane method you use for casting time in 1e Initiative.
    10. If at any point a new party enters the fray during Initiative rounds, repeat the Surprise process (above).

Author: Rick

A DM for *mumble* years, I've been playing AD&D since junior high. I've currently got two separate campaigns running, both in Mystara. I've been told when they handed out hobbies, I stood in the short lines. I actively cycle tour, kayak, play board games, read, develop home automation software, play Stars!, volunteer with the International and National American Red Cross, and work on a never-ending stream of home repairs. In my wake I've left paintball, medieval full-contact combat (SCA), computer gaming, Heroclix, and kite construction.

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