The anonymity of the Chofetz Chaim

"Everyone knows" that the Chafetz Chaim's (1838-1933) initial publication, חפץ חיים (Vilna 1873), was published anonymously, and that even when selling the book he did not identify himself as its author.

Here is the title page:

The approbations inside do not identify the author either. I am not here to debunk the anonymity as a myth, but it is interesting that his name, or at least initials and Russified surname, is definitely on the title page - in Russian - И. М. Каганъ:

Please note that in all likelihood many, if not most, readers of this book could not read Russian.