Encounter ranges in old D&D

Before I go any further, I want to mention something about the title of this article. My term "old D&D" is an attempt at a coinage — basically, everything from so-called 0e through 2e, and any retroclones derived therefrom. If there's already a term for this (OSR seems a bit more expansive), then please let me know.

Anyway, the subject of this article is something I call encounter ranges. This is basically a replacement for the mechanics of surprise. The end result is fairly similar, but it broadens and sharpens our concept, all at the same time.

Surprise!

Basic mechanics

The idea is that each party of an encounter makes a 1d6 roll before anything else happens to determine their encounter range. This is in place of the old surprise roll. This is called the Encounter Roll, and it determines the approximate distance at which the other party is detected, as follows:

Roll 1d6	Encounter distance
0 or less	10’
1	20’
2	30’
3	60’
4	120’
5	180’
6	300’
7 or more	420’

The first party to spot the other always gets a free round to act, but this is spoiled if the encounter range is especially distant. Of course, they can always choose to conceal themselves and even ambush an approaching enemy.

Modifiers

As with surprise rolls, either party may have bonuses or penalties based on their training, as well as circumstances. All surprise roll modifiers can be turned into encounter roll modifiers. For instance, if a creature's description says that they surprise victims on 1-4 of 1d6, it means their opponents' encounter rolls are at -2. Likewise, if creature is only surprised 1 of 1d6, it means that its own encounter rolls are at +1.

In addition, assess the most advantageous sense for detecting another party, and apply modifiers for that. For instance, if another party is very quiet (-2) but unconcealed in open terrain (+2), then their opponent's encounter roll is at +2. Generally, the maximum magnitude of these situational modifiers should be ±3, and those extremes are only intended for absolutes. In most cases, the modifier will be ±1 or 2, at most.

Keep in mind that certain animals and monsters may have an exceptional sense of smell. This means that scent has to be considered for sense-based modifiers, making it significantly more difficult to surprise such beings.

Thief skills

It's always been an open question as to how thief skills interact with surprise, and so it is with encounter ranges. The simplest interpretation is that a successful use of thief skills allows a thief to ignore an opponent's encounter roll result, simply getting as close as he or she wants to other parties, or even bypassing them completely. The GM should if either or both skills (i.e. Hide In Shadows or Move Silently) should be rolled.

If a skulking thief fails his or her stealth skill rolls, this merely means that an ordinary encounter roll is made, and the thief still benefits from moving quietly, possibly under concealment.

Wrapping it up

Anyway, it's just an idea. In many ways, my encounter roll is almost equivalent to the old surprise roll, but it tells you a little more about the disposition of things. First of all, it tells you how far apart parties are when an encounter occurs, and second of all, it tells you who sees the other first. Its hard to imagine that almost half (4/9) of encounters should see both parties detecting each other at exactly the same time, but that's what the old surprise roll called for.