“Shiwasu” another name for December in Japan
It is expression of Japan’s own month.
Japanese-style month titles ”Shi=師=Priest” “wasu=走=running” December.
The Priest is busy with god’s events at the end of the year.
January is “Mutsuki”. 睦月
February is “Kisaragi”. 如月
March is “Yayoi”. 弥生
April is “Uzuki”. 卯月
May is “Satsuki”. 皐月
June is “Minazuki”. 水無月
July is “Fumizuki”. 文月
August is “Hazuki”. 葉月
September is “Nagatsuki”. 長月
October is “Kaminazuki”. 神無月
November is “Shimotsuki”. 霜月
December is “Shiwasu”. 師走