I first became interested in Twelve Kingdoms when my best friend recommended the anime to me. At that time, we were not aware of the novels. I have a tendency to avoid incomplete anime or manga, as I've had too many disappointing experiences in the past (One Piece being a prime example). However, my friend's description was enough to convince me to give it a try.
I ended up loving the anime, although I did get confused at times. Fortunately, my friend was there to help me understand. Getting into Twelve Kingdoms also brought some great memories, like the Mistaken Identity of the Blue Frog Incident (which she still teases me about). When my friend discovered the novels and managed to obtain them, I eagerly read them.
Of course, there are differences between the novel and the anime. Adapting one medium to another is never easy. Fuyumi Ono's novel is just as good as the anime. Even though it eliminates one of my favorite anime characters (I have a soft spot for nerdy girls), I understand that there wasn't enough time to include her in the novel while still telling Youko's story.
The world building in the novel is outstanding and very creative. While some of the concepts may not be entirely revolutionary in China and Japan, they are fresh and new to me as an American reader. Compared to the typical whitewashed British romanticized medievalism and shallow Irish mythology that I'm used to in American fiction, Twelve Kingdoms is a breath of fresh air.
I don't have much experience with novels from East Asia, but I can say that Twelve Kingdoms reads like an American novel in the best way. It has strong descriptions and a writing style that engages the reader. The plot of the first novel is excellent, with believable characters, twists, and suspense. I love Youko and root for her throughout the story. I also have a soft spot for Rakushun (I'm not ashamed to admit that I squee whenever he appears).
In conclusion, I highly recommend Twelve Kingdoms Volume 1. It's a great read with a captivating story, well-developed characters, and a unique world. I give it 4.5 out of 5 stars and can't wait to read the rest of the series.