the fourth day of the month / four days

the third day of the month / three days

all day

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”)

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

nineteenth day of the month

fifteenth day of the month

eighteenth day of the month

sixteenth day of the month

the thirtieth day of a month / thirty days