Claim: Mingma Sherpa climbed nine 8000er mountains as a guide before going to Japan for work, but he returned in 2009 to climb the remaining five; he and his brother only used oxygen on four of the 14 8000ers.
Evidence: Until Mingma climbed nine 8000ers as a Sherpa guide and then went to Japan for work. In 2009 Mingma returned to Nepal and climbed the remaining 5 other 8000ers. The Sherpa brothers used supplementary oxygen only on the four highest mountains out of all 8000ers.