The nation set to elect woman prime minister in landmark first
Over the last two decades, the country has had more than 10 leaders.
Actually, a specialist compares taking up the nation's top job to drinking from a "poisoned chalice".
But why does the country keep changing leaders? It's due in part of it being a "one-party democracy", explains Prof James Brown of Temple University in Japan.
The Liberal Democratic Party's control on the political landscape means the primary rivalry originates within the party, rather than from external parties.
"So within the LDP there are vicious struggles within various groups - they all want their own faction to get the leadership position."
"Thus although you might be chosen as leader, as soon as you're in power, you have many individuals manoeuvring to try to get you out again."
Key Factors Behind Rapid Turnover
- One-party dominance limits external competition
- Internal factional rivalries fuel power struggles
- The prime minister's position is often described as a "poisoned chalice"
- Political stability remains difficult to achieve despite financial power
