The nation set to choose female prime minister in historic first

In the past twenty years, the country has seen more than 10 prime ministers.

In fact, one expert likens taking up the nation's top job to taking a "poisoned chalice".

However, what is the reason does the country keep changing leaders? This is partly because of it being a "single-party system", says Professor James Brown of Temple University Japan.

The Liberal Democratic Party's control on the country's politics means the main political competition comes from within the party, rather than from opposition groups.

"Therefore inside the LDP there are intense conflicts within various groups - they all desire their own clique to get the top job."

"So even though you could be selected as leader, the moment you're in office, you have dozens of people manoeuvring to try to remove you again."

Key Factors Behind Frequent Changes

• Single-party rule restricts outside challenges
• Internal factional rivalries drive power struggles
• The leadership role is often described as a "poisoned chalice"
• Government continuity remains difficult to achieve despite economic strength