The official campaign period for the July 7 by-elections in nine districts of the Tokyo Metropolitan Assembly kicked off on Friday.
The Liberal Democratic Party and the regional party Tomin First no Kai, to which Tokyo Gov. Yuriko Koike serves as special adviser, are competing to become the biggest group in the assembly. Both parties are backing Koike, 71, in the Tokyo gubernatorial election, which is also on July 7.
The Constitutional Democratic Party of Japan hopes to pick up seats by campaigning in step with former member Renho, 56, who is challenging Koike for the governor's post.