Japan set to elect woman prime minister in landmark first

In the past twenty years, the country has had over ten prime ministers.

In fact, a specialist compares assuming the nation's top job to drinking from a "cursed cup".

But why does the country keep changing leaders? This is partly because of it being a "one-party democracy", explains Professor James Brown of Temple University Japan.

The LDP's grip on the political landscape means the primary rivalry originates within the party, instead of from external parties.

"Therefore inside the LDP there are intense conflicts within different factions - they all want their own clique to secure the top job."

"Thus although you could be selected as leader, as soon as you're in office, you have dozens of people manoeuvring to try to remove you again."

Main Reasons Behind Rapid Turnover

• One-party dominance restricts external competition
• Party infighting drive leadership contests
• The leadership role is frequently called a "poisoned chalice"
• Government continuity remains difficult to achieve despite economic strength