1 vs 4 kings is a theoretical win for the 4 kings. 1 vs 3 is mostly a theoretical draw. The game is drawn when both players make 25 consecutive king moves without capturing.

Another interesting variant that comes from the Frisian draughts community is called "FRYSK". You just play with the Frisian rules but start with 5 vs 5. So you just skip the opening theory and dive s…

I see. It seems that you are already a few steps ahead indeed. However, if you want to be completely correct, there is one additional rule that can make a FEN require additional information for …