The Assassin's Touch (Sano Ichiro Series #10)

It is a lost art, passed down by the ancients in great secrecy:Dim-mak. It is death, by the lightest touch of a finger. Sano Ichiro, tenuous in the new regime as the shogun’s second-in-command, does not have the luxury of skepticism? another senior official is dead, a fingerprint lightly glazed into his skin.
 
Sano’s wife Reiko has an investigation of her own: a beautiful, proud, and hopelessly poor woman has confessed to murdering her family. Yet the pieces do not fit, and as Reiko looks deeper into the woman’s life as a hinin? a moral outcast, shunned by the world? inexplicable connections appear between her investigation and Sano’s.
 
As Reiko’s questions spiral her further into the squalor of life as a hinin, Sano and Hirata?his most loyal samurai? pursure their prey, uncovering an intricate tapestry of betrayal woven into the highest levels of the new regime. But they are no match for the one who has mastered dim-mak, a warrior who will strike all those who cross him or his path? even Reiko.