Japan set to choose female prime minister in landmark first

In the past twenty years, Japan has seen more than 10 leaders.

Actually, one expert likens taking up the country's top job to taking a "poisoned chalice".

But why does the country frequently replace leaders? This is partly because of it being a "one-party democracy", says Prof James Brown of Temple University in Japan.

The LDP's grip on the political landscape means the main political competition originates within the party, rather than from external parties.

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

"So even though you might be chosen as prime minister, as soon as you're in power, you have many individuals scheming to try to get you out again."

Main Reasons Behind Rapid Turnover

• One-party dominance limits external competition
• Party infighting drive power struggles
• The leadership role is often described as a "poisoned chalice"
• Government continuity remains elusive despite economic strength