Campaigning began Thursday for the Oct. 26 House of Councilors by-election in Saitama Prefecture, which is widely seen as a litmus test of voter sentiment for the House of Representatives general election expected next month.
Although there are three candidates, the by-election is considered as a faceoff between two of them, one backed by Prime Minister Junichiro Koizumi's Liberal Democratic Party and the other by the Democratic Party of Japan.
It is the first Diet election since Koizumi was re-elected as LDP chief and launched his new Cabinet last month.
Masakazu Sekiguchi, 50, a former member of the Saitama Prefectural Assembly, is running on an LDP ticket, while the DPJ is fielding Chiyako Shimada, 41, a dentist who used to be a TV anchorwoman. The third candidate is Sachiyo Abe, 55, a former Upper House member fielded by the Japanese Communist Party.