Mark The DateThere has been a fair amount of discussion around calendars and time-keeping lately (   ). Time is the important but ill-considered corollary of space that girds location-based exploration play. As Eric at Methods & Madness notes, much has been made of the Quantum Ogre problem, which constitutes railroading-in-space (whether you go east or west, you meet the ogre), but the practice of railroading-in-time, lets for now call it the Quantum Birthday problem, is generally more accepted (whatever day you arrive in town, it is the ogre's birthday).
This is an issue that I flagged in my review of Willowby Hall, as that adventure assumes a floating timeline of events anchored to the point in time at which the party arrives at the titular manor. In my review I expressed that this felt "videogamey" to me, and though I proposed that within a campaign setting one could simply assign the events of the module to a specific date and time in one's calendar, there was an element of this that felt unsatisfying to me. While old-school play proceeds with the assumption that not all content will be explored, when the content is a more-or-less static locale, there exists at least the possibility that it may eventually be visited, or at the very least recycled into different venues. A time-specific adventure feels, perhaps aptly, far more fleeting; if it is missed, it is missed forever (assuming that it is a unique incident, and not a regularly reoccurring one).
That being said, there are a number of techniques, new and old, such as rumours or job boards, that are used by Referees in order to direct players to the spaces where particular adventures occur, and here I would like to outline such techniques that can be used to orient players along the temporal axis as well.
I draw inspiration here from the Shin Megami Tensei: Persona series (or at least entries 3 to 5) in which the calendar serves an incredibly important role in directing player activities. The calendars in each game forecast different predictable or semi-predictable events (phases of the moon, weather, schedules of targets) that circumscribe the possible actions the player can make on a given day, as well as provide deadlines by which certain activities must be completed.
Persona 4 may provide the most interesting example in this case, as its calendar system is the most dynamic. In Persona 3, the calendar is marked by phases of the moon, which are regular and predictable, and the player is shown the entire month's calendar in advance. 4, by contrast, relies on a weather schedule which, while predetermined in the game's code, is not so easily inferred through natural logic on a blind playthrough; only a week is shown in advance. Therefore, while in 3 the amount of time given to complete the next phase of the dungeon will always take roughly 27 days, in 4 the deadline is based around when the next foggy day will be; if one spends too much time tarrying with other activities, they may find themselves hard pressed to finish the dungeon in time and avoid a fail state. Notably, despite this irregularity, the rules for what events and activities occur during which weather states is predictable.
I will list several techniques to be used in conjunction with a calendar and a campaign timeline of events to forecast an ordered logic around time that can be used to clue players in on when the action is, so to speak. Like the principle behind the Three Clue Rule, these techniques have their effect amplified the more are used, and the more redundancy there is, particularly when you wish players to have the possibility of discovering extremely unique time-sensitive events (e.g. occurs on one particular day, or even a few particular hours, and then never again).
Day & Night
Phases of the Moon
Seasons & Weather
|The Errant Weather Table|
Festivals & Habits
Both these larger scale "festivals" and smaller scale "habits" should be mirrored in the underworld/wilderness, not just civilization. Is there a week perhaps where all the dragons in the region meet on a mountain summit for a moot, to resolve grudges, redraw borders, renew allegiances, and pay debts? Do the fae commemorate each solstice with a procession of The Wild Hunt? Do the Goblins have Goblin Mardi Gras?
The MarketThe seasons dictate production, and production dictates activity. Being able to signal to players the state of the economy can provide yet more clues, and give guidance to the Referee about what types of adventures will occur. Economically depressed cities will have high incidence of crimes and political instability; prosperous regions will have frequent caravans patrolling routes that will make attractive targets for bandits and intelligent monsters; areas rich in natural resources may be targets for invasions, assassinations, or coups.
|The Errant Inflation Table|
On a broader, more infrastructural level, the party can hire retainers whose sole purpose is to observe and report from different areas of the setting; say, one such person posted in each of the four major cities of the realm. Of course, the players will need to invest in some communication network in order to facilitate speedy arrival of such information, whether that be a courier service, messenger pigeons, or magical message sending. Ideally they would also have invested in reliable and fast transportation in order to capitalize on such information; vehicles and mounts and ships, and at the domain level investment in infrastructure like roads and (if a higher magic campaign) teleportation networks (I would, if running this, circumscribe such networks to only be able to have a limited number of nodes and only be situateed and transport through leylines, in order to implement a strategic layer for the players in the most efficient configuration of this network).
Cheating, of a sort
First is taking advantage of character rosters and retainers. Players can distribute them strategically throughout the setting, such that if at the end of one session they hear that the Tomb of Tarluk will open for one week before closing again for a century, they can start next session assuming control of their characters in the region already near the Tomb of Tarluk. Metagamey? Perhaps. But we're playing a game, and the aspect of player skill was finding the information and having the setup to be able to capitalize on it; plus if a PC several miles away is aware of something happening, surely the one located closer to it is too.
Second is affording some in game method of time travel. If you've got adventures in your campaign like Willowby Hall that essentially take place on one day specific day in your calendar, and your players discover it in the aftermath, I would also place around the campaign world a limited number of items, locations, or characters that allow the PCs a circumscribed form of time travel. Essentially I'd let them go to a specific place and time for X hours before being brought back to the present. Make whatever magic sends them off specifically have some sort of causality limiter so you don't have to worry about all the butterfly effect ramifications and paradoxes (unless that's your bag); they keep the treasure and etc., dead NPCs remain dead, everything else in the timeline remains mostly intact.
Enterprising players who want to get some more information on what they might find nearby Turnip Hill might pay a sage, who will directly tell them when and where the events of Willowby Hall will occur. Less solvent players may have to settle for the rumours from a bard, or from a local tavern, where whispers of a planned heist into Bonebreaker Tom's castle may be circulating. Players who miss going to this region during this period will soon hear about the aftermath of Bonebreaker Tom's rampage via rumour, and may decide to either follow the trail of the giants and the adventurers, or go on a quest for a time travel Macguffin to get back to the start date of the adventure.