A cultural movement in American pop-culture which had precursors in The '60s, but began fully in The '80s and ended at the late 2000s (if it's really ended at all). The movement marked an intense trend towards heavy interest in Eastern Culture, especially Japanese, and its influence therein on American and European pop-culture.
Somewhat of a counterpart to The British Invasion; whereas the British Invasion marked a heavy influence of British music and musicians on the music industry, the Japanese Invasion marked a heavy influence of Japanese visual media on American visual media, especially animation and comics.
The Invasion can be noted to have begun as early as the release of The Magnificent Seven, a remake of the Akira Kurosawa film The Seven Samurai, in 1960; its counterpart in the animation world came the following year with Alakazam the Great, the dubbing of the Osamu Tezuka film Journey to the West. Throughout the 1960s films from Japan, especially Samurai films, were brought over to the US - at first through remakes, and then as the originals themselves, albeit mostly for the "Art House" market. At the same time cartoons that would one day be known worldwide as anime were dubbed and shown on children's TV as novelty series - most notably, Astro Boy, Speed Racer, Gigantor, and Kimba the White Lion.
Throughout The '70s Japanese animation began to influence American culture. Japanese animation companies had proven proficient enough - and most importantly, inexpensive enough - that animation studios began outsourcing work to Japan, primarily for Inbetweening. The incoming funds for animation from America, combined with the overall success of Japan's manufacturing industries, created an environment ripe for animation, and established the careers of many of the industry's pillar directors. By the end of the decade, Space Battleship Yamato was brought to the US under the title Starblazers, becoming the harbinger of things to come.
Samurai films continued to be brought over, as a counterpart to Chinese and Hong Kong Kung-Fu movies, but were generally regarded as schlock entertainment, barring the works of Akira Kurosawa. "Ninja" entered the American Vernacular, and became exceedingly prominent in film, TV, and especially comic books. Finally, Japanese films were thrown a saving throw in the last years of the decade, in the form of a Science Fantasy film known as Star Wars. Heavily influenced by Eastern philosophy and mysticism, Samurai aesthetics, and directly based on the works of Akira Kurosawa, Star Wars became the link between the East and the West in storytelling.
Following Starblazers came the dub of Battle of the Planets and it became glaringly obvious to US investors that Japan couldn't just create inexpensive animation, but inexpensive gorgeous animation. The '80s are difficult to imagine without Japan's influence, as pop-culture of the day was inundated with shows ostensibly created by and for the US but animated in Japan. Combining Japan's highly-developed animation techniques with American investment capabilities (read: deep pockets) made possible The Transformers, G.I. Joe, SilverHawks, Thunder Cats and many other cartoons, some of which remain popular even today.
Just as the influx of American funds into Japan helped create the animation of the 70s, the greater influx in the 80s allowed for a boom of animation in Japan, with shows like Voltron and Robotech becoming as popular in the US as, if not more so than, their Japanese-originated counterparts. Slowly, American audiences became aware of that these shows were part of a distinctly Japanese artform. The seminal moment of anime in the US came with the release of AKIRA in national theaters. Shown completely uncut with no localization whatsoever Akira forced the American public to acknowledge that Japanese animation (or "Japanimation" as it came to be known) was an entirely different style than Western Animation for all intents and purposes. The '80s also brought the rise of home Video Games, and out of the rubble of The Great Video Game Crash of 1983 came a small Japanese company who would drive the industry for the next 20 years: Nintendo.
The latter half of the 1980s saw more and more imports of Japanese products with part of their marketability being that they were from Japan. Electronic companies like Sony, and car companies like Mazda, didn't try to hide their Japanese roots; instead, they rather reveled in the fact. As Back to the Future said it, "the best stuff in the world comes from Japan," had become an accepted truth in the US, superseding the previous belief that the US produced the best products in the world. During this time, the karate craze saw a revival with The Karate Kid film series. The '80s also saw the first deliberate efforts by Japanese publishers to crack the US market when Shogakukan established VIZ Media in 1986 as a US-based but wholly owned subsidiary to lead the charge, soon to be followed by homegrown US importers like Central Park Media, ADV Films, and Funimation.
The '90s saw the height of the Invasion, as anything Japan-related became hot-selling items, especially Japanese visual media. Fansubs became prominent in media black markets as a way to see "Japanimation" shows which hadn't been brought over to the US. VIZ started publishing "Flipped" versions of Shogakukan Manga converted to left-to-right format for the US market scoring their first breakout hit with Ranma ½. The anime version of Ranma became the first major anime television series be dubbed without any localization or bowdlerization in 1993, something only made possible by the then-burgeoning home video market which freed Viz and their dubbing contractors The Ocean Group from the shackles of broadcast censorship. Sailor Moon followed in 1995, albeit in a much-censored and bowdlerised broadcast form. Both of these shows arrived just in time to generate two of the first internet-based fandoms. Other shows were being dubbed and broadcast on television with varying degrees of success, with those deemed "too intense" for broadcast were relegated directly into the home video market. Unfortunately, thanks to The Rule of First Adopters much of this early product was Hentai with naughty tentacles, thereby damning all anime with the stigma of All Anime Is Hentai. Bad dubbing, bad video transfers, and the ever-present hentai in the children's sections of video rental stores due to the Animation Age Ghetto meant Japanese animation remained a niche product.
But the style was granted one last saving throw just as popularity seemed to be waning the most. The rise of Cartoon Network and the establishment of its action-oriented animation block, Toonami, first brought back shows like Thunder Cats, and then rebroadcast the Macross Saga of Robotech. Then, Toonami broadcast the original run of Sailor Moon, which proved successful enough to warrant the dubbing of more episodes which had never been dubbed before. The Pokémon TV series began airing on broadcast TV, as well, which attracted younger audiences. Finally, it was the broadcast of Funimation's newly-acquired series, Dragon Ball Z, that served as the Heroic Second Wind for Japanese animation. In the span of about two years, "Japanimation" went from being a dying fad, to the household "anime" that is known today.
Japanese games, especially those from Sega and Nintendo, flooded the market and re-centered the video game industry from California to Japan. Mario and Sonic, two Japanese creations, became the iconic generals of the Console Wars, while Pokémon, Street Fighter, The Legend of Zelda, Castlevania, Final Fantasy, Star Fox, Metroid, Kirby, and others put the question into the mind of many Americans whether the US would ever regain prominence in the video game world.
The Turn of the Millennium brought with it the advent of The Internet, and solidified the ubiquity of Japanese culture in the US. Suddenly, these strange foods like Pocky and Ramune become wanted items, which by the end of the decade would become relative mainstays in comic shops and gaming stores. eBay and Internet shops made it possible to buy products directly from Japan, and these Japanese companies were not blind to the possibility of marketing in the US. While still found primarily in hobby, game, and comic shops, many products, such as snap-together mecha models, vinyl figurines, mini-figurines, wallscrolls, etc. have become as commonplace as American goods, and have only been altered insomuch as being printed with English text. In fact, by 2004, anime, manga, and video games had become Japan's single most valuable export, ahead of cars and electronics.
The full effect on visual media came to a head when Western animation began to adopt Animesque qualities. Some shows, such as Teen Titans and Totally Spies! played this to the nines, made as stereotypically Japanese as possible, sometimes including Japanese openings. Others, such as Megas XLR used the visuals as an obvious homage to their influences. Kappa Mikey's premise necessitated it to be animesque. Still others, now the vast majority, like Samurai Jack, Ben 10, and Avatar: The Last Airbender, simply were animesque because that was the style the animators preferred, without any conscious effort to make a "Western Anime".
The earlier years of The New '10s, on the other hand, saw a backlash of sorts, as the Invasion reeled back from American shores. More recent works were treated by some with either indifference or outright disgust, which was ironically helped by the same ubiquity made possible in part through the Internet: more mediocre works became available to audiences in contrast to the relatively filtered novelties of the 90s and oughties. Some pessimistic observers claimed that "anime is dead". Possible reasons included a persistent Animation Age Ghetto, the apparent lack of reliable, professional critics' references, and the industry's (perceived) ever-greater focus on pandering to the otaku market at the expense of casual and foreign fans. For video games, The Seventh Generation of Console Video Games was when Japan lost its dominance of the industry to the West due to lack of experience with HD game development (this being the generation where consoles all switched from standard definition to high definition outside of the Wii). Game development costs sharply rose, and many Japanese developers were unable to properly fund development of these newer HD titles. In addition, the rise of mobile gaming led to the decline of console sales in Japan, and many developers and consumers jumped ship to mobile systems and phones. Many of the genres they made were no longer extremely popular and mainstream, and poor attempts to Westernize their games outside of Nintendo alienated fans of the original franchises.
In the US, anime saw a decline from the tumultuous times faced by American anime companies (due in thanks to piracy, Network Decay, and the general economy) along with the rough times the general Japanese economy faces (which has been ongoing since 1990).
However, the later years saw a resurgence of popularity in Eastern gaming (thanks to key innovations in many of Japan's favorite genres and developers getting used to HD development, as well as the stagnation of AAA Western games and the increase of terrible business practices by Western developers like microtransactions and lootboxes, which Japanese developers tend to avoid outside of Mobile games), the revival of Toonami, the advent of legal streaming, the attendance numbers of large anime cons growing rapidly each year, breakout titles such as Attack on Titan and One-Punch Man, simuldubs, and the continued general presence of Japanese culture. Calling the Invasion over may be premature, and the invasion may in fact be facing a new beginning. In fact, with the rise of streaming and "cord cutters", the stability of anime sales during a time when other forms of American media were suffering caught the attention of major businesses like Netflix, Amazon, AT&T and Sony, which are stepping up to the plate themselves by funding original series and doing their own licensing and dubbing.
Also noteworthy is that Japanese visual media has had an impact on other English-speaking Western countries, particularly Canada, Australia, but probably not in the UK. It is present on mainstream television in Canada and Australia, and works such as Canada's Scott Pilgrim or Australia's OEL Manga The Dreaming demonstrate its influence on the media of those countries.
Despite it all, the one country who was the most influenced by the cultural movement would be France. Plenty of the biggest importers of manga (such as Glenat) were French, and most animesque works are of French origin. Not to mention the fact that there are channels such as Mangas that are 24 hour anime channelsnote , manga rival Franco-Belgian comics in sales and that plenty of Japanese adult novels are sold there. The Louvre, by far one of the biggest museums in Paris, even collaborated with Nintendo to release an application on 3DS devices that makes touring through this extremely big museum even easier. If anything it seems that the latest incarnation of Japonisme has been absorbed into the country and is probably also never ever going to disappear from French shores.
See also Japan Takes Over the World, a scenario which would be this Invasion taken to its logical extreme (prevalent in 80's sci-fi works like Blade Runner, but may pop up in other works out of this time frame too). Compare with Korean Wave, the influx of Korean pop culture that somewhat succeeded the Japanese Invasion. Has nothing to do with other literal invasions by Japan.