The Lake Baikal International Ice Marathon has attracted a growing number of participants since it was established a decade ago, and about 200 runners, including 11 Japanese, challenged one of the world's toughest endurance races this year.

The Siberian marathon is "mentally harder than running through a desert," said Kyo Satani, a 41-year-old runner from Tokyo, comparing the event with the Sahara Marathon in Africa in which he participated last year.

"You cannot figure out how far you have run" because of the monotonous frozen scenery of the Siberian lake, Satani said. The restaurateur ran the 42.195 km distance across the world's oldest and deepest freshwater lake on March 6.