This is Book Two of Sword of the Taka Samurai, by Katherine M. Lawrence. The prior book in the series, Cold Blood: Yamabuki vs. the Sword Master, drew off of the design framework of Cold Saké: Yamabuki vs. the Undead, a standalone book, so we just kept the pattern going.
The repetition of “Cold” in the series titles is reinforced by the use of consistent brush lettering. The diagonal top and bottom borders motif, established in the Cold Saké cover, helps unite the Yamabuki books.
For the illustration, I drew from ancient woodblock prints for inspiration, abstracting and recoloring them to fit the characters.