It is said that before road improvements were carried out, traversing this steep slope of over 500 meters posed significant challenges. In 1618, Kuroda Nagamasa (1568-1623), the first daimyo of Fukuoka, encountered great difficulty climbing this slope while transporting a massive stone from Kyushu to Nikko to dedicate a stone torii gate at Toshogu Shrine. It is said that the laborers needed to pull the stone up the slope required an amount of rice equivalent to Jikkoku (equivalent to 2,000 labourers), which is why it is named 'Jikkoku-zaka'.