Trial on Mount Koya

Hiro Hittori Shinobi Mystery Book #6

By Susan Spann


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Brought to you by OBS Reviewer Daniele



Master ninja Hiro Hattori and Jesuit Father Mateo head up to Mount Koya, only to find themselves embroiled in yet another mystery, this time in a Shingon Buddhist temple atop one of Japan’s most sacred peaks.

November 1565: Master ninja Hiro Hattori and Portuguese Jesuit Father Mateo travel to a Buddhist temple at the summit of Mount Koya, carrying a secret message for an Iga spy posing as a priest on the sacred mountain. When a snowstorm strikes the peak, a killer begins murdering the temple’s priests and posing them as Buddhist judges of the afterlife–the Kings of Hell. Hiro and Father Mateo must unravel the mystery before the remaining priests–including Father Mateo–become unwilling members of the killer’s grisly council of the dead.


Trial on Mount Koya, the sixth book in the fascinating Shinobi Mystery Series, is full of period detail and exceptionally developed characters, a well-done homage to Agatha Christie’s And Then There Were None.

I really enjoy this series, and when I read that author Spann considered this her love letter to Christie and all things mystery, I knew I would be hooked.  As an admirer of Spann and a lover of Christie, I am not disappointed.  In this installment, we find Hiro and Father Mateo on Mount Koya at Myo-in, one of the most sacred Buddhist temples.  They are there to deliver a message to Iga spy Ringa and expect to be on their way in the morning, but a blizzard hits the summit, trapping them, and Ringa is found murdered and posed as one of the Buddhist judges of the afterlife.  Hiro fears that Ringa’s cover is blown, leading to his death, but when other priests are also murdered and posed as other judges, Hiro and Mateo must work together to stop the murderer before everyone in the temple, including Mateo, die.

An isolated group of people without contact to the outside world with a killer on the loose has become a common foundation for a many a mystery book, popular because it has proven time and time again that it works.  In Trial on Mount Koya, it is a perfect setup.  The isolation brings a sense of urgency to the tale.

Our hero Hiro, being a trained assassin and shinobi (ninja), has always been a level-headed sleuth, never allowing his emotions to get in the way of an investigation.  However, here we see a different side of Hiro.  He is grieving over the events in Betrayal at Iga and is haunted by someone’s death feeling certain that he is to blame.  Influenced more by this than his usual intuition and fact-finding, he jumps to some conclusions that impede the investigation.  His fear of failing Mateo also influences every action and thought.  We see a totally different Hiro, the man more than just the accomplished ninja.

Over the course of the series, Hiro and Mateo’s relationship grows from protector and protected to genuine friendship and devotion to each other.  More than just an oath to carry out an assignment and uphold the honor of Iga, a job, Hiro now considers Father Mateo a brother.

Hiro and Mateo are well-developed characters, growing over the course of the series, but the characters central to Trial on Mount Koya are also well defined.  Spann provides a backstory for each of the priests and pilgrims, and it helps readers relate to them and inspires a sense of connection.  Readers care about these characters and worry for their safety and mortality.  As always, the meticulous attention to detail and Spann’s obvious love of Japanese culture shine through making for a fascinating journey back to sixteenth-century Japan.

Trial on Mount Koya can be read as a standalone mystery, but I do suggest reading the entire series to fully appreciate Hiro and Mateo.  I highly recommend it to any historical fiction or mystery reader.

*OBS would like to thank the publisher for supplying a free copy of this title in exchange for an honest review as part of their ongoing blog tour*