The first western explorers to discover the col were George Mallory and Guy Bullock on the 1921 British Mount Everest reconnaissance expedition although it was only Bullock who actually reached it.
Lho La was also investigated by Bill Tilman and Edmund Wigram on the 1935 British Mount Everest reconnaissance expedition but, like the 1921 explorers, they also preferred the North Col route for a summit attempt.[REF][REF] .