A platform for performance of personal combat martial arts is made with a concave upper surface having a central generally flat region for main performance surrounded by a border region that slopes upwardly to the platform periphery, so that instead of the traditional impasse and fight interruption experienced when a combatant is forced into the border region, ropes or corners of conventional flat fight rings, the action tends to continue and automatically gravitate back into the main central region without interruption. A full-height constraint net that slopes upwardly and inwardly further urges combatants away from the periphery and safely prevents bodily ejection, thus protecting ringside spectators while providing all spectators with a good view of the sports action.