By Tim Kelly and Joseph Campbell

TOKYO (Reuters) -Japan stands a good chance of having its first woman prime minister or its youngest leader in the modern era after a vote on Saturday to pick the head of the nation’s ruling party.

The front-runners in the potentially historic Liberal Democratic Party election are conservative nationalist Sanae Takaichi, 64, and her more moderate rival Shinjiro Koizumi, 44. Opinion polls suggest Cabinet Secretary Yoshimasa Hayashi, 64, may also be a contender.

They are among five candidates vying to replace Prime Minister Shigeru Ishiba, who is stepping down after a series of electoral defeats.

The next leader is likely to become premier as the LDP is the biggest group in parliament, but that is not assured as the party – which has run Japan for almost

See Full Page