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

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

In fact, one expert likens taking up the country's top job to taking a "cursed cup".

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

The Liberal Democratic Party's control on the country's politics means the primary rivalry originates inside the party, instead of from external parties.

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

"Thus although you could be chosen as prime minister, as soon as you're in office, you have many individuals scheming to try to get you out again."

Main Reasons Behind Frequent Changes

• One-party dominance restricts external competition
• Party infighting fuel leadership contests
• The leadership role is often described as a "poisoned chalice"
• Government continuity remains elusive despite financial power