Definition
A season word (kigo in Japanese) is a reference to the season. Theses references are generally complied in collections as enumerations (kiyose) or annotated with an example list (saijiki).Usefulness
It is used to fix haiku (and its moment) in the "Cosmos", in our sensible environment and the perception we have of it. Due to their culture imbued with animism, Japanese are very close to Nature. Through shintô, a direct contact with the world of sensations enables them to develop an emotional resonance system linked to natural phenomenons. So they insert their emotions in the seasonal cycle.There are four seasons : Spring, Summer, Autumn and Winter. New Year's Day is a special "season". When Modern Japan comes from the lunar calendar to solar calendar, it wouldn't be possible to decide in which season to place New Year's Day.
Through allusions to vegetation, to big or little animals, to insects, to works, to rituals, to the meteorology, to stars, Collections allow to place a haiku in the year with a precision of two weeks.
A problem
arises. In Japan, seasonal phenomenons are not at the same date over the
whole country...