the fifth day of the month / five days

the tenth day of the month / ten days

fifteenth day of the month

fifty days / Short for 五十日の祝 (ika no iwai): a Heian-period celebration on the 50th day after a child's birth / Short for 五十日の餅 (ika no mochii): mochi fed to the child during ika no iwai

五日 (itsuka, go-nichi, “fifth (5th) day”) / 十日 (tōka, jū-nichi, “tenth (10th) day”) / 十五日 (jūgo-nichi, “fifteenth (15th) day”) / 二十日 (hatsuka, nijū-nichi, “twentieth (20th) day”)

(chiefly Buddhist) temple

the twentieth day of the month / twenty days / Short for 二十日鼠 (hatsuka nezumi): a house mouse

every month

every month

(dialect, Kagoshima) every month