The nation set to choose female prime minister in historic first

In the past twenty years, the country has seen over ten leaders.

In fact, one expert likens taking up the country's highest office to taking a "poisoned chalice".

But why does the country frequently replace prime ministers? It's due in part of it being a "single-party system", explains Prof James Brown of Temple University in Japan.

The LDP's grip on the political landscape means the primary rivalry originates inside the party, rather than from external parties.

"So within the LDP there are intense conflicts within various groups - they all want their own faction to get the leadership position."

"So even though you could be selected as leader, the moment you're in power, you have many individuals scheming to try to remove you again."

Key Factors Behind Frequent Changes

• Single-party rule limits outside challenges
• Internal factional rivalries drive leadership contests
• The prime minister's position is frequently called a "cursed position"
• Government continuity stays difficult to achieve despite financial power