A total of 471 people are preparing to run in the July 20 election for the House of Councilors, the upper chamber of Japan's parliament, as of Tuesday, a survey shows.

The ruling Liberal Democratic Party will field candidates in all prefectural constituencies, after completing the delayed procedures of fielding a second candidate in Tokyo and a candidate in Osaka.

Meanwhile, opposition parties are expected to fight over Upper House seats in over half of the 32 constituencies where one seat each is up for grabs.