Prime Minister Shigeru Ishiba likes the nitty gritty of policy, cigarettes and making models, but his dream job as Japanese leader could go up in smoke this weekend.

Opinion polls suggest that Ishiba's coalition could lose its majority in Upper House elections Sunday, a result that might push him to resign.

The Liberal Democratic Party (LDP) has governed Japan almost continuously since 1955, but whether anyone wants to replace Ishiba is another matter.