Over the years, the Assassin's Creed franchise has taken fans everywhere from Ancient Egypt to the Carribean's Golden Age of Piracy. The Chronicles spin-off branched out even further than some other games, covering 1526 China in the midst of the Ming Dynasty, 1841 India during a war between the Sikh Empire and the East India Company, and 1918 Russia immediately following the October Revolution. As such, fan speculations and rumors always seem to discuss where the next game will take place, but it seems Assassin's Creed keeps skipping out on its most desired, and perhaps best, location for a game.
According to Ubisoft itself, one of the most demanded settings is Japan, with fans seemingly drawn either to the Feudal Era or the Satsuma Rebellion (which also ended the Samurai class). It would also be once thing if this was just fan demand, but Ubisoft has also fed the sharks by teasing a Japanese Assassin's Creed setting several times now (if years ago).
Namely, back in Assassin's Creed 3, three images (seen below) appear in the opening that were unfitting of its Colonial America time period. These symbols are the Eye of Horus, the Greek letter Omega, and a Torri - a gate for sacred Japanese sites. Since then, of course, Assassin's Creed Origins and Assassin's Creed Odyssey have been released, which thereby correspond with the Eye of Horus and Omega. The Torri, however, remains unvisited.
Furthermore, there was the Abstergo E-mail (also seen below) that details possible ancestors (and potential locations) to be explored via Desmond Miles' genes. Many of these have since been explored, such is the case for Egypt even if the time period is far off. But on this list, fans of the franchise can easily spot the Ashikaga Shogunate as a potential location.
So, with this time period and setting being in high demand and heavily teased by Ubisoft, it almost seems like a matter of "when" and not "if." If the aforementioned Assassin's Creed 3 image was to be a pattern, then it seems like it would rationally come next, yet all rumors indicate the next installment will be Assassin's Creed Ragnarok. And at this point, it seems far more likely than a Japan setting due to the sheer volume of rumors and leaks. This traditionally happens prior to an announcement, so it fits the mold of prior releases. That said, a recent insider has stated that most Assassin's Creed Ragnarok leaks are not accurate, meaning that there could be some huge surprises on the horizon.
Assuming those images did intend to tease a Japanese setting, one could speculate that it is in development. It's possible, after all, due to Ubisoft's intricate development cycle for Assassin's Creed. Origins, which is largely responsible for breaking the series' franchise fatigue, took an extra year for development, as well as Assassin's Creed 2020. It's possible that Japan was meant to be released sooner but was relegated to a later release date to allow it more development time if the next game does go the way of vikings.
A secondary reason could be the currently slight saturation of games set in Japan. The aforementioned development delay could be due to games like Sekiro: Shadows Die Twice that released last year and Ghost of Tsushima coming this year, which means Ubisoft is biding its time to release the game instead of going all out with it. Of course, this is all speculation at this time.
The bottom line is that all signs point toward the next game having vikings and being titled Assasin's Creed Ragnarok, while the demand for a Japanese Assassin's Creed game remains at an all-time high. Thus far, leaks make it sound like Ragnarok will continue the trend of Origins and Odyssey pushing the franchise forward, complete with a rumored co-op mode, selectable protagonists name Jora, and an interesting Berserker Mode, so many may not be that upset by visiting this time and place instead of Japan. But even if that is the case, there's a good chance many are still clamoring for a Japan-based game.
Ubisoft has a tendency to tease future games in its newest releases (AC: Ragnarok was first teased in Division 2), so eagle-eyed fans may want to keep an eye out for any similar imagery in Ragnarok. While it doesn't seem likely that Assassin's Creed 2020 will be Japan, there's no telling what 2021 will bring if its popularity remains high. That's all if Ubisoft doesn't throw a curve ball, of course.
Assassin's Creed Ragnarok is rumored to be in development.