16 Cheshvan is the yartzeit of Rav Shach, R' Elazar Menachem Man ben R' Azriel ZY"A. The Steipler told someone that needed advice on something, to speak to Rav Shach, explaining that since Rav Shach is always thinking in learning, whatever comes out of his mouth is Daas Torah. That's one of the great things that the Holy Steipler had to say about him.
The following is an excerpt from Rav Shach's will:
I would also like to ask all those talmidim who know that they received some benefit from me, whether in Torah, whether in yiras Hashem or whether in good character traits, to act kindly towards me and to learn for the elevation of my neshama, even a single mishnah, or a single mussar thought, and this shall be my reward, since I too sacrificed myself for the sake of your success in learning. And if it will be in my power to do anything or to advocate good for you, I will do so beli neder.
Zchuso Yogen Aleinu