Soukou is one of the twenty four solar terms which divides a year into twenty four periods according to the lunar calendar and refers to October 23rd or 24th.
Soukou, written in 霜 (frost) 降(fall), means, as the name suggests, the time for frost to start coming down. People nowadays may think that sounds too early to start thinking about frost. However, in older times when there was no clock to keep track of time, people relied on an end of season indication to let them know what was around the corner meteorologically. Soukou also helped people know what would be needed to prepare for the coming season, which was vital for their yearly survival.
The arrival of Soukou indicates all vegetation and crops would have a dusting of winter white soon and farmers need to get ready for it. At this time farmers also started preparing for the arrival of the real winter in Ritttou which immediately follows Soukou.
Once Soukou arrives, a wintry wind starts blowing and mountain foliage starts displaying their autumn colors. By Rittou, winter will be fast approaching around the corner.
Japan’s pace still seems to flow well with the twenty four solar terms.