The nation on course to elect woman prime minister in historic first

Over the last two decades, the country has seen more than 10 leaders.

Actually, one expert likens taking up the country's highest office to drinking from a "poisoned chalice".

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

The Liberal Democratic Party's control on the political landscape means the primary rivalry originates inside the party, instead of from opposition groups.

"Therefore inside the LDP there are intense conflicts within various groups - they all want their own faction to secure the top job."

"So even though you might be selected as leader, as soon as you're in power, you have dozens of people scheming to try to get you out again."

Main Reasons Behind Rapid Turnover

• One-party dominance limits external competition
• Party infighting fuel power struggles
• The leadership role is often described as a "cursed position"
• Political stability stays elusive despite economic strength