The context I am thinking of is converting a board game into a video game or app. Of course, I can't manufacture a physical copy of the game without permission, but does the same apply to a virtual version? My understanding is that copyright protects only the particular manner of an author’s expression. This means that the board game is copyrighted, but a video game with the same mechanics is not. Is that the case?
Game mechanics are not copyright able. However, the images, words used, description of the rules are all copyright. If the original games is the source of the video game then the video game is a derivative work. If the original game is only the inspiration and the look and feel is different then this is OK. Which is which will turn on the actual facts.