Since there were 5 slams held in '77 & only 3 in '86, I was wondering if the ITF or any other organization had any rule in place as to what constituted a Calendar Grand Slam those years. Lendl made the finals of all 3 slams in '86, winning 2, had he won all 3 of them what would that have counted as? Would he have had to win the '87 AO for a Grand Slam to count? In '77, if a player won 4 slams in a row, regardless of which ones(since there were 5 that year), would it have counted as a Grand Slam? Or would they have to win all 5?