February is called Kisaragi in the lunar calendar in Japan.
The main theory is that when Risshun (around February 4) passing, it gradually gets warmer but cold back again to a very cold weather on the contrary, due to which people wear more clothes, also written as Wear more clothes. On the other hand, another theory is that it is written as Getting warmer weather, or The rehabilitation of plants, the time of their coming into bud.

Risshun (start of Spring) is one of the 24 solar terms, which indicates the term up to Usui or rain water, around February 19. The traditional East Asian calendars evenly divide a year by using the solar movement to the 24 terms, coinciding the dates with the named seasons in the lunar calendar.

It seems to be understood that each name indicates a certain date only in most cases, but exactly speaking, it represents the seasons as well as the terms, Well-known is that there are two shis of Geshi and Touji (Toushi) two-buns of shun-bun and shu-bun, four of which is Nishi Nibun. Another one is 4 ritsu of Risshun (start of Sprinmg), Rikka (start of Summer), Risshuu (start of Autumn), Rittou (start of Winter), which are called 8 terms, coupled with 2 shis two buns and 4 ritsu. The said 24 solar terms consist of the further divided terms from the above. Today, most people are not so conscious of things other than the above.

Usui, or rain water, means that the time when what falls from the sky changes from snow to rain and snow melts, and finally first spring strong wind blows. In Japan, in the previous season before Spring comes, are there cold days continued about for 3 days and warmer days for the next 4 days. Its repetitions finally bring forth warmer and warmer days to Spring, which is called Sankan Shion, or 3 cold and 4 warm days.

This was a popular phrase used in the northern China and Korean Peninsula. It seems to be caused by the strong and weak cycle of the high atmospheric pressure in Siberia. In Japan, the cycle is slightly different, but this way of saying is here to stay and this time of year, the phrase is often heard. Experiencing Sankan Shion after the mid February, we long for a warm spring coming soon with a kind of excitement, don not we?