Lair Hunting

This is a rules extensionEx which provides rules for searching a 6-mile map hex for monster lairs.1) The AD&D rules don't provide a system for locating monster lairs intentionally, only through travel. The system on this page is a slightly modified version of the rule found in ACKS, one of the better B/X-based games. Specifically, in the ACKS Lairs & Encounters book.

Each hex which is not patrolled by a settlement contains a number of lairs as indicated in the Lairs rules.

A 5-mile hex can be intentionally searched for lairs. Of course, not all hexes will have lairs, and it is impossible to know how many a hex contains at a given time without the use of magic. Because treasure types are used for outdoor lairs, it’s possible for a lair to be very profitable or to return nothing at all.

Procedure (hex movement)

This procedure should be used with our Hex Movement system. If you don't use that system, see below for the miles movement procedure.

Party travels to the hex they'd like to search for lairs. Once they've paid the MP to enter the hex, they can spend MP to search for lairs.

To search the hex, the party spends MP as though they were entering the hex. Every time this is done, two types of rolls are made by the DM. This can be done repeatedly as long as the party can pay the MP.

Lair check: The DM rolls a d20, with a 1-7 indicating a lair is found (if one exists, see DM's note at bottom of page).

If flying, two checks are made instead of one. (The DM will resolve one roll and then the other. If the party decides to stop lair hunting after the first roll is resolved, then the second roll is discarded.)

If a ranger is in the party, a lair is found on 1-11, or 1-9 if the party is flying.

Random encounter check: A random encounter check is made for the hex. Random encounter checks are made every time the party spends the MP to lair hunt, rather than at the normal times defined by DMG 47. These too can result in a lair via the monster’s % In Lair chance.

The party may split up, in which case the resultant smaller parties each get their own checks. These parties will not be close enough to assist in an encounter (without magic).

Procedure (miles movement)

Party travels to the hex they'd like to search for lairs.

Every hour (assume a 10 hour adventuring day)2) Not sure if I remember the source for this. Might just be a reasonable number we deduced. , two checks are made:

Lair check: The DM checks with a d20 on the below table, based on party daily movement speed. Be sure to adjust speed for the terrain of the hex.

If a ranger is in the party, the check is at +4. This bonus is reduced to +2 if the party is flying.

If flying, a check is made every 30 minutes instead of hourly.

Random encounter check: Random encounter checks are made every hour instead of at the normal times defined by DMG 47. These too can result in a lair via the monster’s % In Lair chance.

The party may split up, in which case the resultant smaller parties each get their own checks. These parties will not be close enough to assist in an encounter (without magic).

Miles of Movement per Day	Target Roll	Miles of Movement per Day	Target Roll
11 or less	18	108-119	9
12-23	17	120-131	8
24-35	16	132-143	7
36-47	15	144-155	6
48-59	14	156-167	5
60-71	13	168-179	4
72-83	12	180-191	3
84-95	11	192 or more	2
96-107	10

At the table

This system can be an attractive choice if an expedition completes with an hour or two to spare in a session and the party wants to do something other than start a new expedition. In that way, it's similar to the treasure maps system. Sometimes, a group might want to do this for an entire session, since it can be a fun interlude from other things, and is basically always an option.

DMs may desire to roll up lairs in advance for each of the hex terrain types (see Appendix B), and then use them when lairs come up on a hex. That being said, this can certainly be done on the fly. Though there is always the chance of rolling a Men lair, which typically involves a lot of rolling for the classed characters' magic items.

DM note: How many lairs?

How many lairs are in a hex? Extrapolating from Dave Arneson's system:3)https://nagorascorner.blogspot.com/2015/01/the-post-rationalised-universe-or-what.html roll a d10: 1-4 = that many lairs, 5-0 = no lairs. Players should of course not know how many lairs are in a hex.

If a hex is determined to have zero lairs, yet a random encounter in that hex hits the % in Lair roll, the lair can still be placed if you'd like. It must be a new lair that's just popped up!