I think I first heard of this book when it first came out, but I had the wrong impression. It actually is fictional, not a memoir.
There are two levels on which I care to write about this:
First of all, the book and history itself. It's fascinating, and it offers a lot of information on the mysterious world of the geisha. It has taught me a lot about geishas overal and prompted my researching to find out how much of it is actually true. It turns out that, for the most part, it describes well the overall life and circumstances of a training and working geisha.
Second, the book is very easy to read and sounds more like a true memoir than the novel that it actually is. It feels like a true representation of an honest person. The book has an honest and personal feel about it. Highly recommended!
(Further observations)
The relationships between all of the people involved are extremely complex and fluid, and the amount of trust individuals can have for each other can never be counted on. An individual could hope to be honest in all interactions, but the complexity of the society overall definitely shapes and colors everything.
I suppose that it is overall a romance, but not really. There is a long time love, but said love is not directly addressed until the end. How loves are expected and addressed are a unique and complex thing for geishas; love per se is not considered in their world. The one thing that appears to be assumed is that geishas are expected to have sex with their clients. This apparently is not necessarily standard – some did, some didn't. It definitely was not a default of all geishas.)