Arc System Works announced River City Saga: Three Kingdoms in a surprise reveal of the release date which is actually not that far off.
Kunio Kun's adventures have taken him all over the world and the next one seems to be set in China, during the third century AD. While the setting might sound a bit odd, the game seems to be taking cues from the River City Ransom mechanic, which sounds promising on its own.
Furthermore, it wouldn't be the first time Kunio visited an era in the past as Downtown Special: Kunio Kun's Historical Period Drama did a similar thing, under the guise of putting on a play in the school. Whether the same explanation will be used for Three Kingdoms remains to be seen.
River City Saga: Three Kingdoms release date has been set for December 16, 2021, on Nintendo Switch and it's safe to assume we will get to know more by that time.
That is not the only platform where we will get to play RCS: Three Kingdoms, however, as the game will come to PlayStation 4 and PC via Steam at some point in 2022. In the case of PlayStation, the game will probably be playable on PS5 as well but nothing has been confirmed officially yet.
The initial reveal was completely in Japanese but since the game is headed for Steam in 2022, it will almost certainly have a Western version as well so fans can rest easy for now.