No prob. The novel is available on Amazon here:
Masaru It was originally written for a young adult audience, but I really liked it. Strong, sympathetic characters. Fast-moving plot with some twists and turns. And best of all, the author has an excellent grasp of Japanese language and the culture of 17th century Japan.
A relatively historical consideration of the Shimabara Rebellion can be found Christ’s Samurai: The True Story of The Shimabara Rebellion by Jonathan Clements.
It is nice that there is another book on this. There are not a great deal of English books on The Shimabara Rebellion