Some things, for example, like a geisha’s virginity being auctioned to the highest bidder is something I think Iwasaki refuted but Liza Dalby wrote about briefly in her book Geisha. (which you might find interesting, she’s a North American woman who lived with and “became a geisha”)

Another book I really recommend is Autobiography of a Geisha. Kyoto geisha were always the privileged ones, so to say, but there were women who entertained all over the country and were much more like prostitutes. This book is about one of them, and it’s absolutely heartbreaking, but a great read, usually the one I recommend as a follow-up to Memoirs of a Geisha.