Japan set to choose woman prime minister in landmark first

Over the last two decades, the country has seen over ten leaders.

Actually, a specialist compares taking up the country's highest office to drinking from a "cursed cup".

However, what is the reason does the country keep changing prime ministers? This is partly because of it being a "one-party democracy", says Professor James Brown of Temple University in Japan.

The LDP's grip on the political landscape means the primary rivalry comes from inside the party, instead of from opposition groups.

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

"Thus although you might be chosen as prime minister, the moment you're in office, you have dozens of people scheming to try to remove you again."

Key Factors Behind Frequent Changes

• Single-party rule limits outside challenges
• Party infighting fuel leadership contests
• The prime minister's position is frequently called a "poisoned chalice"
• Political stability stays difficult to achieve despite financial power