The nation on course to elect woman prime minister in historic first

Over the last two decades, Japan has seen over ten prime ministers.

In fact, a specialist likens assuming the nation's highest office to taking a "poisoned chalice".

But why does the country keep changing prime ministers? This is partly because of it being a "single-party system", says Prof James Brown of Temple University in Japan.

The LDP's grip on the political landscape means the main political competition comes from within the party, rather than from external parties.

"So within the LDP there are intense conflicts within various groups - they all desire their own clique to secure the leadership position."

"So even though you could be selected as prime minister, as soon as you're in office, you have many individuals manoeuvring to try to get you out again."

Main Reasons Behind Frequent Changes

• Single-party rule restricts outside challenges
• Party infighting drive power struggles
• The leadership role is often described as a "poisoned chalice"
• Political stability stays elusive despite financial power