Jijian
Jijian is the sixteenth and last mester of the standard Didduan calendar. It is twenty-three days in length by the usual reckoning, although a few civilizations vary in when they site the beginning and end of the mester, potentially making it slightly longer or shorter. Jijian follows the mester of Ienoan, and precedes Jiricin. During the entire mester of Jijian, all Diddu is overcast and dark as night, which leads many cultures to metaphorically associate this mester with darkness and death. (Though in a different way than Gurunda and Derean, which are more literally associated with death—or rather with undeath.)
Conditions
The mester of Jijian is primarily noted for its darkness. The sky above Diddu becomes dark and opaque, casting the land below in perpetual shadow. Because of its absorptive properties, the darkened sky produces a greenhouse effect that somewhat compensates for the reduced sunlight reaching the surface, and means that the surface temperature of Diddu is only slightly cooler during Jijian than it is during most other mesters (and certainly warmer than it is during Ienoan). While the temperature is little affected, however, visibility is another matter; the level of light during Jijian is during the day slightly darker than the average night during most other mesters, and during the night is all but pitch black. While some organisms do adapt to the lower-light conditions, most humans do not, and find their range of vision sharply impaired by the lightlessness. (The temperature of parts of Diddu's atmosphere actually increases during Jijian, but at altitudes where the increased temperature has no direct effect on most people's doings.)
While the sky during Jijian is said to become black, technically it is actually very dark purple, but it is dark enough to appear pure black to all but the most acute human eyes. Nor does the opacity affect all the air; the part of the air that becomes opaque (or at least less transparent) comprises a layer about 1.7 kilometers thick, starting roughly six kilometers above the ground. The air below that layer actually becomes slightly more clear than usual, and seems to take on a slight minty flavor to some people, though not everyone seems able to taste this.
Although the darkened sky is the most noticeable and most notorious condition during Jijian, there are other smaller changes that also take place. Some parts of the world undergo slight distortions, which go so far as to significantly affect the coastlines of some continents. Odd sounds occur seemingly randomly over Diddu's surface, their source unclear—mostly rustlings, moans, and low whistling noises. Other local changes occur in specific areas.
Transitions
During the transition from Ienoan to Jijian, the darkess begins before the warming. Over a period of about two days, the sky gradually darkens, until it reaches its maximal level of opacity. One day later, the temperature then rises over a period of three days until finally stabilizing. Jijian is conventionally held to begin at the start of the rise in temperature, although a few cultures instead hold the mester to begin at the incipiency of the darkness instead, making it three days longer.
As Jijian turns into Jiricin, the darkness dissipates over a period of about two days. This is accompanied by a slight rise in temperature, but this time it occurs simultaneously with the change in opacity, and in any case is much less pronounced than the temperature change between Ienoan to Jijian. Usually Jijian is considered to end, and Jiricin to commence, after the first day, but again, this is subject to some variation; some cultures hold Jijian to end as soon as the sky starts to lighten, or not until after it has completely lost its opacity after the second day. Together with the variation in the mester's onset, this means that Jijian can be variously held to be as short as twenty-two days or as long as twenty-seven.
Creatures
Most of Diddu's almestral creatures are active during Jijian, though some of them undergo a few changes. For one, some, though few, humans and other sophonts change form to some sort of beast during this period, making them a kind of mestral turnskin. Most changes are more subtle; the fur, feathers, or scales of many animals grow darker during Jijian, while a few do just the opposite and turn lighter instead. A few, including the brown bear and several varieties of lizard, literally glow during Jijian, most with a soft white light but some in more vivid colors.
A few varieties of plant, too, are altered during Jijian, most notoriously the ramble tree, which gets its name from its tendency to become ambulatory and wander around during this mester. The ramble tree is a special case, however; most plants that change during Jijian remain sessile, but alter their form. The ghost thorn, for instance, otherwise an innocuous bush with whitish foliage, during Jijian—and only during Jijian—grows long, sharp, envenomed thorns.
Magic
Jijian lends itself well to magics of concealment and illusion, and to a lesser extent of dreams; it is an efficient time to create talismans with powers such as invisibility, silence, the creation of illusory forms, and so forth. Among the popular talismans created during this mester are thieves' cloaks, masking stones, and phantasmagorica. Mestral mages specializing in the magics of Jijian are known as euphronae.
Because of the efficacy of magics on Jijian useful for subterfuge and espionage, many businesses and agencies are on high alert during this period, taking especial precautions to secure themselves against spies and intruders. Employment for guards and counterspies is high during Jijian, as well as for mages with spells useful for these purposes. This incidentally leads to Jijian being a particularly bad month in many places for mundane burglars without access to the mestral magics all this supplemental security is able to protect against, though where the public guard is not augmented they can still prey on commoners who don't have access to this extra protection.
Holidays
The biggest holiday to occur in Jijian is Lovers' Day, which is commemmorated on the fourth day of Jijian, or the 381st day of the year. Lovers' Day is a day dedicated to the pursual of new loves and the consummation of old ones; it is said that more people on Diddu lose their virginity on Lovers' Day than on any three other days combined, though since not all cultures observe Lovers' Day this is probably an exaggeration (although it may very well be true in some of those cultures that do observe it). Amorous couples on Lovers' Day often copulate in places they wouldn't dare to on other days of the year, taking advantage of the cover of darkness—and of the fact that such activities are considered largely less unacceptable on Lovers' Day than elsewhen.
In some cultures the association of Jijian with clandestine activities is played with through the observance of Thievesnight, on which people may set each other challenges to try to steal some particular object. Thievesnight has been outlawed in some locales because of the opportunity it gives real thieves to mask their activities, but it remains popular in many places.
The last day of Jijian is sometimes observed in honor of the new year, but more often this is celebrated on the first day of Jiricin, called the Great Dawn.
Herbs
Among the common herbs that grow during Jijian, camelwort is useful in magics of camouflage (and itself can alter its colors and patterns to blend in with its background, making it hard to spot); leermint masks flavors and odors; and cackleweed is good for producing auditory illusions. Some herbs have a less direct and obvious connection with the mester's strengths; swebber induces sleep, and dalaway protects against mental enchantments. Rarer herbs available during Jijian include starweed, which can be used for various strange transformations, and swickroot, useful for all sorts of illusions.
Curiously, one herb grows during Diddu that seems to go directly against the mester's usual associations. Verity is a small plant with white leaves and pale blue flowers that emits a soft glow, making it easy to find in the darkness of Jijian. Although its light is too faint to be very useful in itself, verity can be used in many concoctions and enchantments that counter darkness and illusions. Because its nature so contravenes Jijian's normal magical effects, many people believe that verity may have an unnatural origin. It is commonly thought to have been an artificial creation intentionally placed on Diddu by Tira, the Angel of Truth, or by some other agent.