December 29th is considered a day to be avoided because, in Japan, the number nine, which can be read as 'ku' in Japanese, is linked to the Japanese word for suffering (contrastingly, this day is selected in some areas because one way to read the number 29 in Japanese is "fuku," which is also the word for happiness).
12月29日は、日本では「九」が苦しむにつながるので避けるべきとされる（逆に29を『福』と読み替えて、この日に餅を搗く地域も有る）。