Walt Sheldon was a pulp staple, with dozens of published crime and adventure stories in the 1950's and 1960's. His novel output, both under his own name and various pseudonyms (Shelly Walters, Shel Walker, etc), was also impressive. The Blue Kimono Kill (1965) was Mr. Sheldon's first novel published under his own name.
The Blue Kimono Kill introduces the reader to Dr. Robert Marlin - anthropologist on loan to the US government. The book opens with his arrival in Tokyo on business. Marlin is ostensibly researching one of his theories, and using the bored housewives of US soldiers as subject matter. The government is keen to make sure morale stays high for the military men and Marlin's equally keen to get some work done. At least, he thinks he is. It doesn't take long for Marlin to get bored. The military wives are a desperate, lonely lot, with straying husbands and eager appetites. Although in most circumstances, he'd love to do some further "research" (nudgity wink wink leer), the recurring theme of debauchery is wearing him down.
While drinking his troubles away at the bar, Marlin remembers an old war buddy - Master Sergeant Harry Crowell. Crowell saved Marlin's life a time or two in Korea, although the two have drifted out of touch since then. Marlin calls on Crowell... only to learn that his friend has been brutally murdered in a back alley. Worse yet, Crowell was carrying a load of uncut heroin at the time. A bit of hanky-panky is standard operating procedure, but Crowell seems to have been a major dealer. Crowell's not just dead, he's an embarrassment, and his widow, Masako, is left without husband or pension.
Marlin throws himself into the mystery surrounding Crowell's death with great glee. Although he's supposedly out to redeem his friend's legacy, it is clear that Marlin's mostly bored. His anthropological theories generally discuss the myriad of strange ways that folks change when surrounded by foreign cultures, and Marlin himself is no exception. Isolated, alone and surrounded by a society that he struggles to understand, Marlin adapts by leaping headlong into the role of secret agent.
Although he's far from dumb, Marlin wanders into one trap after the next. His initial instinct - that Crowell was close to busting a heroin ring, not leading one - proves correct. But every other assumption he makes winds up getting him betrayed or thumped in the head (often both). He is, for a professional people-watcher, a terrible judge of character. Still, the enthusiasm of his amateurism explorations swings the day. Marlin's cynical in all things, but also stubborn, and, whatever his motives, he's determined to get to the bottom of Crowell's murders. Mr. Sheldon does an exceptional job of layering Marlin's character. Marlin is a bitter, selfish man pretending to be a white knight. But underneath, in rare moments, we see that he actually does care - about Crowell, about the women he meets and about doing the right thing. He may seem an endless well of snark, but his softer side is what ultimately endears him to the reader.
Marlin's surrounded by an entertaining cast of characters. Crowell (in an opening scene) is a dimwitted but ambitious man. His wife, Masako, is painted as enigmatic, but has her emotional moments - her clear love for Crowell among them. Elsa, Marlin's love interest, is a bonkers expat actress, too clever for her lifestyle and circle of admirers, making up her own language out of sheer boredom. Even the bit characters - a loopy old captain, a snide gossip columnists - are interesting and complex. Although the villains are perhaps the most two-dimensional, Mr. Sheldon does his best to give them a little added depth (the economist Communist and the drug-addicted trigger man are perhaps the two most memorable).
But the real strength of The Blue Kimono Kill isn't the characters - it is the setting. Mr. Sheldon's Tokyo is a phantasmagorical land of flickering neon. His depiction of sushi makes it sound like the stuff from a Roman orgy (difficult to imagine a time where Itsu wasn't on every street corner, isn't it?), and every back alley is crammed with flickering signs, strange smells and sinister characters. There is, undoubtedly, some Rohmer-era Orientalism about The Blue Kimono Kill, but Mr. Sheldon avoids value judgements in favor of alienness. It isn't that the visiting Americans are better (in most cases, they're objectively worse), it is that they're out of place. Japanese culture isn't corrupting Americans, the remoteness is. The soldiers might as well be on the moon. And it works both ways, with the Japanese residents of Tokyo being just as baffled by the Americans.
Equally importantly is Tokyo's hedonist atmosphere - a distant city where "everything goes". Mr. Sheldon (and his moutpiece, Marlin) again blames the alienness. The soldiers are serving in a different dimension, so petty profiteering and adultery are all - if not justified - accepted. Every American that Marlin interacts with has a distinct "here vs home" mentality. At home, they'd never visit prostitutes, sell information or take drugs. The government men collect pornography, the journalists deliberately provoke trouble and the soldiers smuggle tiny pouches of heroin, all because, in a land this unreal, these activities feel like games, not moral decisions. Marlin and Elsa are no different. They throw themselves into their heroic roles because, well, why not? All of Tokyo is a vacation from reality. It isn't until their lives are actually on the line that the excitement sours. The reverse is also true. The Japanese in The Blue Kimono Kill see the Americans as transients and deliberately avoid permanent connections. Even the marriages are depicted as ephemeral; largely relationships of convenience rather than love.
This same ambience shows up in some of the best noir-inflected science fiction, including Lauren Beukes' Zoo City and Richard Russo's Avenging Angel. Both those books are also set in fictionalised versions of real world cities, cities that have plunged into corruption and decadence, where the lines between the real and unreal have started to blur. Like The Blue Kimono Kill, the stories twist and break open when casual explorations - more 'fun and games' - turn into something more sinister and impactful.
The Blue Kimono obviously has its flaws - and being a piece of Cold War era espionage literature based in Tokyo, I suspect you can guess them all already. The plot is a bit random, but the characters are enticing and Mr. Sheldon's Tokyo is an exceptional place. Exotic settings are a dime a dozen (especially when you extend the search to SF/F), but thoughtful depictions of how characters interact with that setting - and are, in turn, shaped by it - are far more rare.