The Fire Kimono is a 2008 mystery novel written by Laura Joh Rowland, set in the Genroku period (AD 1688–1704) in Japan. It is the 13th book in the Sano Ichiro series.

This time, Sano was assigned to a sensitive murder investigation more than four decade old involving a member of the Tokugawa clan, cousin to his lord Shogun Tokugawa Tsunayoshi. The murder apparently occurred during the historical Great Fire of Meireki the destroyed much of Edo city that took the lives of many people in the confusion. Sano was shocked when his mother became embroiled in the case as a primary suspect and learned there were much more to her than he had ever imagined.

Meanwhile, the tension between Sano and Lord Matsudaira reached a boiling point and they were on the verge of open warfare, a situation brought about by the manipulation of Yanagisawa Yoshiyasu who had earlier escaped from exile.
[edit] Plot Summary

In the prologue, a Shinto priest passing by discovered remains of a human unearthed when strong winds toppled an oak tree near the Inari Shrine.

Since his return from Ezogashima, there had been increased in attacks against Sano and against Matsudaira, the attackers wearing insignias from each other's houses. Just as Sano confronted Matsudaira about the latest attack on Sano's wife, Reiko, which Matsudaira flatly denied, both men were summoned by the Shogun.

The shogun informed them that the skeleton of his long lost cousin, Tokugawa Tadatoshi, who was thought to have perished during the Great Fire of Meireki, and charged Sano with the investigation.

Sano barely had time to plan his investigation when his mother, Etsuko, was arrested by Matsudaira's men as the suspect for murdering Tadatoshi. The witness was a Colonel Doi Naokatsu in the service of Matsudaira. Doi was also apparently once Tadatoshi's bodyguard, and Etsuko was a lady-in-waiting to Tadatoshi's household women. Sano was shocked that his mother was not a humble commoner as he had thought, but a scion of the Kumazawa clan, a respected hereditary Tokugawa vassal. Doi claimed to have heard Etsuko plotting with Egen against Tadatoshi, Egen being a monk and Tadatoshi's tutor.

Sano was able to convinced the shogun to allow him bring Etsuko home to facilitate the investigation, but he was dismayed to find his mother less than cooperative. As more and more of the past were uncovered, his mother's position became more and more unfavourable.

Meanwhile, confined to the security of the house due to danger of attacks, Reiko was at last able to help in the investigation by trying to get more information from Etsuko, and from Etsuko's loyal longtime maid, Hana. Reiko was also struggling to win back her young daughter, Akiko, who became alienated from Reiko when Reiko left her behind to go to Ezogashima to rescue her son, Masahiro, as told in the previous novel.

Hirata too had returned from an even longer absence to find that his wife and children had become strangers to him.

Amidst the investigation, Yanagisawa plotted with his son Yoritomo to bring down both Sano and Matsudaira.