I googled this variant. It's called "Flying Kings" and it appears it only exists in international games (which are played on a 10x10 board) and certain "in house" rules. The one thing that seems common is that the King is only allowed to jump over 1 piece at a time (although it can continue in any diagonal direction once it's landed on a vacant square). i.e. it can't jump over 2 or more pieces that have no vacant square between them. Hope that clarifies