The Pearl Diver is the 7th in the Rei Shimura series by Sujata Massey. It has dropped to £2.99 at Kindle UK. I quite liked this series back in DTB days, and apparently some other folks did too - many of the titles have won/been nominated for various awards. £2.99 is not great for old backlist, but WTH...
link:
https://www.amazon.co.uk/Pearl-Diver...dp/B007SNJEOU/
Two other titles in this series are at £2.49 right now as well:
The Bride's Kimono, #5:
https://www.amazon.co.uk/Brides-Kimo...dp/B007SNHQVS/
The Samurai's Daughter, #6:
https://www.amazon.co.uk/Samurais-Da...dp/B007SNJG52/