Night of Yom Kippur- A Yom Kippur Bris:

Some write that it is customary not to hold a Wacht Nacht Torah learning ceremony on the night of Yom Kippur. Others[1], however, write that one is to perform the Wacht Nacht ceremony of learning even on the night of Yom Kippur.

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[1] Zecher Dovid 3:71