Clone Project: 1 or 2 in 6

For the possible simplified near-clone of the LBBs, I wanted to tackle what I think of as effects rolls: rolls to see what happens as a consequence of player actions. We usually see these listed in the rules as "... on the roll of a 1 or a 2 (on a six-sided die)" or similar wording. These are mixed up with a kind of ability roll that works the same way, but there are only a couple abilities described: sensing secret passages, hearing noises through doors, opening stuck doors. Pages 4, 8-9, 11, and 16 list the following d6 rolls:

• pit causes damage: 1 or 2
• search for secret passage: 1 or 2 (elves 1-4)
• sense secret passage: 1 or 2 (elves only)
• open doors: 1 or 2 (1 in 6 for small, light characters)
• spike slips: 5 or 6 in 6
• trap sprung: 1 or 2
• hear noise through door: 1 or 2 (humans 1 only)
• surprised: 1 or 2
• wandering monster (dungeon, city, plains): 6 in 6
• wandering monster (woods, river, desert): 5 or 6 in 6
• wandering monster (swamp, mountains): 4, 5 or 6 in 6
• monster follows after evasive maneuver: 1 or 2
• monster follows through secret passage: 1 in 6

All of the beneficial results listed are low rolls; so are some of the misfortunes, except for spikes slipping or wandering monster encounters. We can regularize these procedures by thinking of them as "roll under target number to avoid an undesirable result". When looked at this way, we can group most of the targets into three types:

In Order To...		Roll <=
Change Situation		2
Avoid Accident		4
Avoid Danger		5

This assumes that:

• the normal situation is for monsters to be quiet, doors to be stuck, secret passages to remain secret;
• triggering a trap, taking damage from a 10' fall, being surprised, or having a spike slip is an accident;
• running into a monster is also accidental, but also a great danger.

You can further adjust these probabilities by modifying the die roll. For example, humans can only hear a noise when listening at a door on 1 in 6, and likewise a small, light character can only open a stuck door on 1 in 6. From these two examples, we can abstract a "difficult task" modifier of +1, which makes any 2 rolled on the d6 a 3, which is a failure for "Change Situation". Similarly, wandering monsters are more likely to appear in more difficult outdoor terrain, so we can just note that the normal chances apply to clear and inhabited regions, but add +1 to the roll if the terrain is difficult, or +2 for swamps and mountains.

Let's apply this to something on page 16 that I left out of the list above: getting lost in the wilderness. The table uses low rolls, so we'll invert them to high rolls, treating this as an "Avoiding Danger" roll: on a 1 to 5, the party doesn't get lost; on a 6, the party is lost. The more confusing the terrain features, the easier it is to get lost: add +1 to the roll for woods and mountains, +2 for swamps and deserts.

This analysis may have been a bit lengthy, but it looks like we can reduce all these rolls to a single three-line table and a couple notes and modifiers.