Voters in mountainous parts of western Japan on Friday began casting early ballots in a van believed to be the nation's first mobile polling booth.

With early voting for the House of Councilors election underway, the four-wheeled polling station was introduced by the city of Hamada, Shimane Prefecture, to make it easier for elderly voters who cannot easily get to polling stations because of limited transport.

Voters received voting slips outside the vehicle and sat in the van's second row of seats to mark their choice before dropping them into the ballot box.

"Voting inside a vehicle was new to me, but I was able to vote just the same," said Susumu Habe, 84, who was the first to cast a ballot in the vehicle.

His 93-year-old cousin, Isao Habe, said it took longer to vote than a normal polling station and the vehicle was smaller than he expected.

The van, accompanied by observers and election board officials, is scheduled to visit 11 locations in three days, staying about an hour to 90 minutes in each spot, according to the local election board.

While 153 voters in the area are covered by the "votemobile," it can also accept votes from people in other areas, the board said.

Voters were notified of the dates and hours for the new early voting method via letters and other means before Friday.