It was called “shamateurism.”

The idea of open tennis tournaments of professionals and amateurs had been discussed for decades and had nearly become reality in 1960, when the International Lawn Tennis Federation, known as the I.L.T.F., narrowly rejected a proposal to approve it. It took eight more years for reason and economics to prevail, and in late March 1968, with Wimbledon and the U.S. Championships already set to become open, the executive committee of the I.L.T.F. voted to authorize a number of open tournaments, including all four Grand Slam events.

It was not quite a full embrace of the concept: the I.L.T.F. still kept in place certain restrictions that dissuaded some amateurs from turning professional. But the pros — or at least most of them — were now welcome.

The British Hard Court Championships, obscure today but significant in that era, happened to be the first stop on the pros’ hastily revised itinerary.

Players like the reigning Wimbledon champion John Newcombe, who had signed with World Championship Tennis, the new circuit backed by the American oil baron Lamar Hunt, did not make the journey. But Rosewall’s and Laver’s group of six players, who were under contract with the promoter George MacCall’s National Tennis League, were eager to take part.

“It was the first, and there was no way I was missing it,” Laver said. “I wanted to be not the headliner by any means, but I wanted to be there. It was in England, and when you start saying England, you also are saying Wimbledon.”