FACTBOX: Leaders of Japan's two main political parties

(Reuters) - Japanese Prime Minister Shinzo Abe's conservative ruling coalition lost its upper house majority in elections on Sunday, but the 52-year-old conservative said he intended to stay on in his post.

The main opposition Democratic Party of Japan was on track to become the biggest party in the upper chamber.

Following are some facts about Abe and Democratic Party leader Ichiro Ozawa.

SHINZO ABE

* Born in 1954 and a third-generation politician, Abe is Japan's first prime minister born after World War Two. He has made revising the U.S.-drafted postwar pacifist constitution and boosting Japan's security profile key planks of his platform.

* His grandfather, Nobusuke Kishi, was a wartime cabinet minister who was imprisoned after the war but never put on trial. Kishi served as prime minister from 1957 to 1960 and had a strong influence on the young Abe.

* Abe's support ratings have sunk to around 30 percent, which some analysts consider a crisis level, on voter outrage over bungled pension records and concern about political corruption.

* The soft-spoken Abe is known for his stylish clothes and a sweet tooth. He and his wife Akie, 45, have no children and Akie has said the couple has fertility problems.

ICHIRO OZAWA

* Born in 1942, Ozawa was first elected to parliament as an LDP candidate at the age of 27 and rose rapidly through the ranks as a protege of party kingpins. LDP secretary-general at the age of 47, he was once considered a candidate for prime minister.

* In 1993, Ozawa left the LDP with about 40 other lawmakers, setting off a chain reaction that ended its four-decade rule and replaced it for a year with a reform-minded coalition. Since 1994, when the LDP returned to power, Ozawa has formed a number of new parties and briefly joined the ruling bloc.

* Ozawa was an early advocate of clarifying the military's ambiguous status under Japan's pacifist constitution, as well as forging a more equal diplomatic partnership with the United States and a bigger role for Japan in Asia.

* Ozawa has a reputation for high-handed decision-making and has suffered from comparisons with more telegenic rivals. He joined the Democrats in 2003 and was elected party chief in April 2006 to serve out the remaining term of his predecessor, who resigned over a failed attempt to discredit an LDP executive.

* Ozawa, who has heart problems, was to rest for one or two days due to fatigue from his election campaigning, a Democratic Party official said.