Korona is a version of Carrom played in Finland.
Like in Carrom, there is a wooden square shaped board usually less than 1 meters wide. The idea of the game is to hit small round pieces with a bigger piece into corner pockets. In the Finnish version you use sticks to hit the big stone instead of using your finger which makes Korona even more similar to billiards than the Carrom.
The pockets are typically larger than in Carrom but there's some space between the pockets and the edge of the board. Therefore it's possible for a piece to go behind the pocket which can sometimes cause some extra trouble.
During a setup the pieces of each player are placed in a tight row against the wall on the opposing side of the board instead of a pattern in the center. There's no bonus pieces in this game. Because all the pieces are separated according to their color, it's possible for a skillful player to put all the pieces in a pocket with only one strike.
Each player in a three or four player game may play with their own colors instead of forming teams with opposing players.
The Swedish Couronne is similar in that it typically has space behind the pockets and uses cues, but the pieces (usually 15 of each colour) are initially placed in the middle. The game is considered to have evolved from American Carrom early in the 20th century.