Two octogenarians are once again competing for the title of the oldest man to reach Mount Everest's summit.
Japan's Yuichiro Miura, 80, and Nepalese climber Min Bahadur Sherchan, 81, are vying for the Guinness World Record against one another five years after they last ascended the treacherous mountain.
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In May 2008, Sherchan, who was 76 at the time, successfully beat 75-year-old Miura to the peak by one day.
Sherchan made the climb in just 340 days, according to the Guinness World Records.
Miura was in the "death zone" on Wednesday -- the area close to Everest's 29,035-foot summit which has little oxygen and is very steep and icy.
Emili Miura told ABC News via email that her father, Yuichiro Miura was "scheduled to make [the] final attempt toward summit" sometime on Wednesday.
By Thursday, Miura posted on his Facebook page he had reached the summit. He will gain the Guinness title, but it may only be for a few days, if the older Sherchan makes it to the top.
Sherchan is currently at Everest's base camp preparing to make his own ascent next week.
Miura has said he took on the challenge of the climb "to face [my] own ultimate limit. It is to honor the great Mother Nature."