Yoshiteru Takahashi, 65, claims to have seen a group of three yetis on his last visit to Nepal, in 2003, but maintains that the light quality during the evening sightings was too poor for him to take photographs.
This time -- his fifth such mission -- his seven-strong team is equipped with state-of-the-art motion-sensitive photographic equipment and they plan to position it along a ridge at an altitude of 4,800 metres in a range of mountains some 200 km from Kathmandu.
"The ones that I saw were small, around 85 cm tall, but it was getting dark and it was difficult to see them properly," said Mr Takahashi.
"I don't know what they are, but they appear to be some sort of hybrid of chimp or orangutang without a tail."
Mr Takahashi and his team plan to stay at their base camp for six weeks to catch a glimpse of a creature, which he described as "shy".
He traces his obsession with a creature that many believe is mythical to his first visit to the Himlayas, in 1971.
"I have climbed the Dhaulagiri (White Mountain) massif four times, and every time, I saw footprints of the yeti," he said.
"In 1971, one of my expedition members saw one of these creatures.
"It looked like a gorilla," he said. "It was only 15 metres away from him and watching for about 40 seconds," he said.
"It was about 150 cm tall and stood on its hind legs, like a man. Its head was covered with long, thick hair and he was certain it was not a bear or a monkey."
In another visit to the region in 1994, Takahashi discovered what he describes as a "bolt-hole," a natural cave that stretched back 5 metres into a rock face at 5,000 metres above sea level.
"Animals had definitely visited the cave and there were more of the footprints in the snow around the mouth of the cavern," he said.
Unfortunately, his camera failed and he couldn't record his find.
"The footprints that I saw were similar to the one photographed by British explorers Eric Shipton and Michael Ward in 1951," Takahashi said.
Found in the Gauri Shankar pocket, those prints were fresh when the mountaineers chanced upon them. The trail continued for nearly 2 km until it finally disappeared on hard ice.
"The ones I found were smaller and thinner, more like a human foot, with an arch between the heel and the toes," Takahashi said.
"There are no animals that leave that sort of track."
He says the creature is known locally as the "migou" or "bongamanche," meaning "man of the forest," and local people regularly bump into the species on their travels in the region.