One of the reasons for the huge loss the ruling Liberal Democratic Party suffered in Sunday's Upper House elections was the party's failure to secure any seats in 18 prefectural districts.
As final results filtered in early Monday, it became clear that LDP candidates could not secure any seats up for grabs in such populous constituencies as Tokyo, Kanagawa and Osaka.
Sunday's elections marked the first time since the LDP was formed through a merger of two other political parties in 1955 that it secured no seats in the Saitama, Aichi, Kyoto and Wakayama districts.
It was also the first time since the Upper House race of 1965 that the LDP failed to win a seat up for grabs in the Tokyo voting district. The Upper House holds elections for half of its members every three years.