The nation set to elect woman prime minister in landmark first

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

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

But why does the country keep changing prime ministers? This is partly because of it being a "single-party system", explains Prof James Brown of Temple University Japan.

The LDP's grip on the country's politics means the primary rivalry originates inside the party, rather than from opposition groups.

"So within the LDP there are vicious struggles within various groups - they all want their own faction to get 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 get you out again."

Main Reasons Behind Frequent Changes

• Single-party rule limits external competition
• Party infighting fuel leadership contests
• The leadership role is often described as a "cursed position"
• Political stability remains elusive despite economic strength