Challengers are tasked with balancing on top of a cylindrical barrel rolling over a downward-slanted 5.4 meter track. As it descends down the track, competitors must constantly move their feet to keep up with the increasing velocity of the barrel. If they can't, they'll ultimately lose their balance and fail.
Although most competitors rode it out the whole obstacle, some competitors (most notably Yamamoto Shingo) leaped midway through in order to avoid losing their balance, but it also increased the risk of touching the water if unsuccessful. Although it was only failed three times, it famously eliminated Yamada Katsumi in SASUKE 11 when Yamada tipped over on the barrel and landed with one leg on each side, and Shiratori Bunpei in SASUKE 14 when he lost his foot rhythm, slipped, and fell in front of the barrel, causing it to hit him in the head as he fell. This obstacle was replaced by the Delta Bridge in SASUKE 16, but returned the next tournament, only to be replaced by the Net Bridge in SASUKE 18 due to the course renewal brought on by Nagano Makoto's kanzenseiha.
Competitor's Success Rate
SASUKE 24-27 Version
This obstacle returned in SASUKE 24 with a much shorter track with a rope at the end. Basically a hybrid of this and the Rope Climb from First Stage. The finishing mat was made much higher, requiring the competitors to roll to the end of the track and jump to the rope before climbing up the rope to get to the platform in order to get to the next obstacle. It proved to function more as a time waster as no one failed there. In SASUKE 25, the ending rope was shortened. Because of this, Yamamoto Shingo was eliminated when he tried to leap halfway through the track. Kanno Hitoshi also failed the obstacle by losing his balance and falling backwards. This also marked the first time that the obstacle took out more than one competitor in a single tournament (along with ANW4). The rope was made longer in SASUKE 26 but the track was angled more downward than before, making it go much faster than in previous tournaments. The obstacle eliminated Travis Furlanic in the tournament, who failed by losing his balance on the rolling portion. This obstacle was replaced by the Spider Walk in SASUKE 28.
This version was also used on American Ninja Warrior 4 and American Ninja Warrior 5 as the fourth obstacle of Stage Two, being replaced by the Butterfly Wall on the next season. It took out some of the best competitors like Travis Rosen, Brian Arnold, and Flip Rodriguez on American Ninja Warrior 4.