Looking for Three Assassins

Don't panic reading the title of this post, I mean figuratively speaking, of course. If you read this post from earlier this month, you know that I recently watched and enjoyed d Bullet Train. Which is based on a novel by Kotaro Isaka. it is actually the second book of a trilogy, starting with Three Assassins (or 3 Assassins, I have seen the title spelled both ways). Okay, so this novel will not feature extensively a train, which is one of the appeals of the film, but all the same, I love crime fiction and I want to read the trilogy in order. I could order it on Amazon, but I think I will buy it at the local bookshop.