The nation on course to choose female prime minister in historic first

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

In fact, a specialist likens assuming the country's top job to taking a "cursed cup".

However, what is the reason does Japan frequently replace prime ministers? This is partly because of it being a "single-party system", says Professor James Brown of Temple University in Japan.

The Liberal Democratic Party's control on the political landscape means the main political competition originates inside the party, rather than from external parties.

"So within the LDP there are vicious struggles within various groups - they all want their own clique to secure the leadership position."

"Thus although you might be selected as prime minister, the moment you're in power, you have many individuals scheming to try to remove you again."

Key Factors Behind Frequent Changes

• One-party dominance restricts outside challenges
• Internal factional rivalries drive power struggles
• The prime minister's position is frequently called a "poisoned chalice"
• Political stability stays elusive despite economic strength