Jomgerd Berthelsen is one of the few Scandinavian players to have reached international fame without ever participating in the World Mornington Crescent Championships. Her attitude to this, the major tournament, remains baffling to MC researchers both in and out of Scandinavia as her only public comment on the matter was "Fish!"
Her main claim to fame was her ingenuitive use of the Hills And Valleys Helix variant that put her at the throne of MC both in Denmark and Sweden for a number of years during the 1950s and certainly was the main reason for the very attractive contracts she landed in the 1960s with both leading Bolivian clubs at that era.
The helix play seemed to have contrasted too heavily with the style of play in Latin America, dominated as it is by a mixture of slow consideration and considerable agility. Berthelsen faded from public view in the autumn of 1972 and from then was only known to make scathing but accurate comments to published play in various smaller international journals.