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

In fact, a specialist likens assuming the country's highest office to drinking from a "poisoned chalice".

However, what is the reason does Japan keep changing prime ministers? This is partly because of it being a "single-party system", explains Professor James Brown of Temple University Japan.

The Liberal Democratic Party's control on the political landscape means the primary rivalry comes from inside the party, rather than from external parties.

"Therefore inside the LDP there are intense conflicts within various groups - they all want their own clique to get the leadership position."

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

Main Reasons Behind Frequent Changes

• Single-party rule limits outside challenges
• Party infighting fuel power struggles
• The leadership role is often described as a "cursed position"
• Political stability remains difficult to achieve despite financial power