THESE DISHES CONFOUND Western notions of what Japanese food should be, in part because diners who haven’t grown up eating the cuisine often encounter it in the limited binary framework of high and low: austere sushi bars where the tab starts at three figures versus quick-turnover ramen shops, with few options in between. In adopting ingredients and techniques from other cultures, the new movement might even uncomfortably recall the Asian-fusion trend that started in the late ’80s, which was spearheaded by chefs of European descent. But where those chefs filtered Japanese cuisine through a Western perspective, taking Japanese elements out of context and subsuming and bending them to their will, today’s chefs are doing the opposite — viewing the West and its culinary traditions through a Japanese lens. As the thinking on diversity in America has evolved from the metaphor of a melting pot to a mosaic, in which each piece keeps its integrity while enriching the whole, the concept of fusion has become archaic, replaced by a more organic understanding of how food changes when people immigrate and have to adapt to the ingredients on hand.

By refuting rigid orthodoxy — and some inchoate standard of authenticity — these chefs remind us that Japanese cuisine is not some repository of edicts past but a lived and living tradition, as well as a pastiche, one that has borrowed unapologetically from other cultures throughout history, despite the country’s long seclusion. Tempura, both dish and word, was a gift from the Portuguese, whose language was brought accidentally to Japan when, in 1543, three Portuguese sailors on a Chinese ship made contact in southern Japan. Jesuit missionaries followed, ultimately passing on a recipe for peixinhos da horta (“little fish of the garden”): green beans dusted in flour and deep-fried.

Curry arrived in the 19th century, during the Meiji era, from India via the British Royal Navy, when the subcontinent was part of the Raj. It was considered a Western dish and thus pricey, until the late 1950s, when Japanese companies started selling instant curry that produced a dish milder and sweeter than either its British or Indian counterpart. Troffer modeled his curry after the best-selling S&B brand but with a lashing of heat; during the colder months, it’s served at Marlow as it often appears in Japan, with pork katsu, a cutlet gilded in panko. Aikawa took his Texas version further afield, finding kinship to Louisiana gumbo and Mexican mole as he wrangled more than two dozen spices trying to strike the right balance, recalibrating by the gram in batch after batch. He serves his curry straight or amped up into a near chili, which is stuffed in a brioche bun and topped by a hot dog that’s been patted down with panko and deep-fried so it suggests a hard-shell taco.

The concept of fusion has become archaic, replaced by a more organic understanding of how food changes when people immigrate.

Ramen, likewise, has no time-honored history. According to George Solt’s “The Untold History of Ramen” (2014), the dish is said to have first appeared in 1910 in Tokyo, under the name shina soba (Chinese noodles); almost vanished during World War II, when flour was strictly rationed and street vendors were banned; and revived with imports of wheat under the midcentury U.S. occupation — when Americans hoped to keep the population sated and therefore invulnerable to the promises of communism — to eventually flourish postwar as a hearty and cheap lunch. Of all Japanese foods, it might be “the most open, the most receptive to change and experimentation,” the American-born chef Ivan Orkin wrote (with Chris Ying) in the 2013 cookbook “Ivan Ramen.”

Japanese chefs must typically apprentice for years before they get the opportunity to run their own kitchens, but Shigetoshi Nakamura won fame for his ramen shop in Tokyo while still in his 20s. Earlier this decade, he opened an eponymous shop on the Lower East Side of Manhattan, and this year he converted the storefront next door to Niche, focusing on mazemen, a version of ramen that largely dispenses with broth. In homage to the neighborhood’s historic Jewish delis, Nakamura cold-smokes salmon in-house and drapes it over noodles in a loose sauce of cod roe and olive oil.

Even the California roll, often held up as an example of sacrilege, is believed to have been invented by a Japanese immigrant chef in the late 1960s, who, finding himself in Los Angeles without a reliable supply of bluefin tuna, swapped in an ingredient more plentiful on the West Coast, one with its own richness and heft: avocado.