I recall, in my twenties, that the Rabbanut in Israel had chosen the Tenth of Teves as an appropriate day for which Kaddish should be recited for those who were murdered in the Holocaust and about whom we do not have the date of their cruel demise. If I remember correctly, it was also when I learned Rabbi Chaim David Halevi’s עשה לך רב, that I came across this idea. That background also prompted me to buy and read his biography, more recently. If you haven’t come across R Chaim David Halevi’s scholarship, I recommend it.
What is the importance of the Tenth of Teves? It is one of the minor fasts that are described explicitly in Tanach. The siege of Yerushalayim our Holy City, during the 1st Temple, began on the 10th of Teves. Symbolically this represented the beginning of a tragic, calamitous, series of unfolding Galus-oriented historical events. Indeed, the 8th and 9th of the Month are also recorded as days identified as sorrowful. This fast represents our existential Galus state and is observed even if it turns out on Friday, Erev Shabbos.
The words used by God to describe these events to the Prophet Yechezkel were the same words used in conjunction with the description of Yom Kippur, the holiest day of the year, on which we fast even if the day falls out on the Shabbos: the words “On this very day” “B’etzem hayom hazeh.”
The Israeli Chief Rabbinate saw in that date, an appropriate day to add the mourning for those who were murdered in the Holocaust. In particular, that date was also chosen as the one to say Kaddish for those whose date of murder is unknown. The policy has been that we have enough sad days and associated fasts, and whilst the Holocaust is surely the major calamity in our history after the temples were destroyed, commemorating it during Nissan isn’t recommended (via Yom Hashoa) because we don’t utilise Nissan for sad events.
The link between the Tenth of Teves and the Holocaust is clear. The fact that the Jews were removed from their Capital Holy city of Jerusalem, and its Holy Temple represents the existential Galus which we find ourselves in today, and which will only be terminated once the Redeemer comes upon Zion, gives it a pointed segue.
In the past, this detail didn’t mean too much to me because I didn’t say Kaddish and sadly, I don’t see many Shules choosing this day (or the ninth of Av) as formally remembering the Holocaust. I do not know why the 10th of Teves would be objectionable to anyone.
These days, I say Kaddish on my father’s a’h Yohr Tzeit, and those of my parent’s parents, and other members of the family who for whom nobody says Kaddish. Accordingly, I now ask myself whether I should also say Kaddish on the Tenth of Teves for members of our family who were murdered on an unknown day during the Holocaust. I can’t think of a reason why I would not. Indeed, I ask myself why anyone who is able to say Kaddish, and knows they had family members who were murdered on an unknown date, would not say Kaddish? It seems straightforward that they should. The only reason I can think of is that this fast is mentioned in Tanach and tacking on other reasons might not be appropriate. I don’t agree however. History for Jews is a chain reaction. It is not the outcome of disparate discrete events.