Japan set to choose woman prime minister in landmark first

In the past twenty years, the country has had over ten leaders.

In fact, a specialist likens taking up the country's top job to taking a "poisoned chalice".

But why does the country frequently replace prime ministers? It's due in part of it being a "one-party democracy", explains 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, instead of from opposition groups.

"Therefore inside the LDP there are vicious struggles within various groups - they all desire their own clique to get the top job."

"Thus although you might be chosen as prime minister, as soon as you're in power, you have dozens of people manoeuvring to try to get you out again."

Main Reasons Behind Frequent Changes

• Single-party rule restricts external competition
• Party infighting fuel leadership contests
• The leadership role is frequently called a "poisoned chalice"
• Political stability stays elusive despite economic strength