The reason, I guess, is that if it were not so, the King could position itself next to the centre square and never be captured, even if it couldn't escape that way as the requirement is to place pieces on all 4 sides.
(peida) Kui vastased tahavad reaalajas mängida, siis peavad nad valima "Tee käik ja jää siia" ja siis F5-klahvi abil ümberlaadima! (TeamBundy) (näita kõiki vihjeid)