In a letter issued Wednesday evening and distributed in all Jewish communities across Israel, the rabbi wrote that in recent years, "the generation which still says Kaddish in memory of relatives killed in the Holocaust is dwindling," and he is therefore asking "anyone who is a relative of the Holocaust righteous and is able to say Kaddish for the transcendence of their souls" to do so.
The rabbi added that "if there is no proper relative, someone else should say the Kaddish." He also said that a candle should be lit in memory of the Holocaust victims and that the Mishnayot (the collection of oral laws forming the basic part of the Talmud) should be read after the prayer.
The 10th of Tevet is also known as the "Holocaust day" set by Israel's Chief Rabbinate 64 years ago, in memory of the Nazis' victims whose date of death is unknown.
"According to Jewish Law, if the day of death is unknown," Rabbi Lau explained, "the relative must choose a special day of the year in which he will fast and say Kaddish."
The 10th of Tevet is one of the three fasts over the Temple's destruction, in addition to the 17th of Tammuz and Tisha B'Av.
It commemorates the siege of Jerusalem by Nebuchadnezzar II of Babylonia, an event which began on the 120th of Tevet and ultimately culminated in the destruction of Solomon's Temple(the First Temple) and the conquest of the Kingdom of Judah (today southern Israel).