Walt Sheldon wrote several books for Gold Medal. He wasn't up there with John D. MacDonald or Charles Williams, but he was a good second-tier author that nobody ever mentions these days. The Blue Kimono kill was published in 1965, and the others a few years later. Though a couple of them have the word kill in the title, they aren't part of any series. They're all standalones.
In The Blue Kimono Kill, cultural anthropologist Bob Marlin is in Japan to do some research. He's reminded that his old friend, Harry Crowell, who saved his life in Korea, is there and decides to look him up. Harry, unfortunately, is recently deceased. Murdered, as a matter of fact, and the crime remains unsolved. Marlin, who turns out to be one of the toughest cultural anthropologists in crime fiction, decides to poke around. Soon he's tangling with hired goons and beautiful women. There's plenty of action and some kinky sex in the grand Gold Medal tradition.
Sheldon writes very well, he's very good with the Tokyo setting, and he knows how to keep a book moving right along. The politics will seem dated to whippersnapper readers, but you old guys shouldn't have any trouble recalling the days of the Red Chinese menace. I enjoyed reading this one again, and I've liked all of Sheldon's Gold Medal books. Check 'em out.
[Digression: Holding and reading this one again, I was reminded of my aunt Birdie. She spent her declining years pretty much as a recluse, reading paperbacks all day, smoking, and drinking bourbon. When Judy and I would visit, she'd tell me to take any of the books I wanted. This is one of those I picked up from her. She had good taste, did Birdie, and I salute her.]