I have been interested in the practice of onmyodo and in the stories and legends of Abe no Seimei ever since watching Abenobashi Mahou Shotengai many years ago. My recent wrap-up effort on my Japan travelogue rekindled my interest, leading me to come across the film online. And despite still having a few hallmarks of 90s film techniques, Onmyoji: The Yin Yang Master is redeemed somewhat by its interesting take on Heian Era history and characters, as well as some of its actors.
Apart from Seimei himself, we also get some historical fiction thrown in through the inclusion of the historical characters of Minamoto no Hiromasa and Prince Sawara, as well as a "hidden history" version of why the Heian Era began. Nomura Mansai works well in the role of Seimei, especially with his naughty kitsune face. Ito Hideaki's Hiromasa was played well too, and Sanada Horiyuki did a good job with the role of Douson, even though the character could have been written with more depth.
The demon and magical sequence effects are a little awkward, but the costumes and sets are great, and the cinematography is otherwise up to contemporary standards. I also liked the use of silence and ambient sound in this film. The plot, however, is a tad confusing; the reason for Douson's hatred does not seem very well explained, and there is a lot of hand-waving and just-so employed. Ignore that, though, and it's not a bad film.