The nation's longest-serving prime minister, Shinzo Abe, visited a Tokyo hospital on Monday as concerns grew over his ability to continue in his post, because of health issues and fatigue from handling the coronavirus crisis.

If Abe is incapacitated, Deputy Prime Minister Taro Aso, who doubles as finance minister, would take over temporarily. If Abe resigned, he would stay on until formally replaced, which would require the ruling Liberal Democratic Party to elect a new leader, who would then be formally elected in the Diet.

Here are details of some likely contenders to take the helm of the world's third-largest economy.