Japan set to elect female prime minister in historic first

Over the last two decades, Japan has seen more than 10 prime ministers.

In fact, a specialist compares assuming the country's highest office to taking a "poisoned chalice".

However, what is the reason does the country frequently replace leaders? This is partly because of it being a "one-party democracy", says Professor James Brown of Temple University Japan.

The LDP's grip on the political landscape means the primary rivalry comes from within the party, rather than from external parties.

"So within the LDP there are vicious struggles within different factions - they all want their own faction to get the top job."

"Thus although you could be selected as leader, 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 limits outside challenges
• Party infighting drive leadership contests
• The prime minister's position is frequently called a "poisoned chalice"
• Political stability remains difficult to achieve despite financial power