 Complete the following phrase:  This was the last challenge match, as the event reverted to a traditional tournament for the 1969 World Snooker Championship, and except for a round-robin stage at the 1971 World Snooker Championship, the event has been played as a single-elimination tournament since. Pulman had been touring snooker clubs as promotional work for the tobacco brand John Player, and the company had sponsored his match against Charlton. The good attendances for the challenge match led to John Player deciding to sponsor the 