Japan's new defence minister, Yuriko Koike, is something of a troubleshooter. And the trouble she needs to get her prime minister out of this time is impending embarrassment in the July 29 election for the upper house. The first woman to hold the post, the 54-year-old has been elected to the House of Representatives five times and replaced Fumio Kyuma, 66, this week with the task of restoring serenity to the embattled Liberal Democratic Party. In the latest polls, Prime Minister Shinzo Abe's popularity has fallen below 30 per cent and the opposition parties rejoiced at the timing of Mr Kyuma's comments. Previously the special security adviser to the prime minister, Ms Koike made all the right noises at the press conference announcing her appointment. 'National defence is an important pillar of a state and there is not a second to be wasted. I will devote myself to my duties seriously,' she said. Ms Koike has also served as environment minister and was responsible for the Northern Territories and Okinawa under prime minister Junichiro Koizumi. The former premier selected her as an 'assassin' candidate to run against rebellious members of his own party. She defeated another LDP politician who refused to back Mr Koizumi over the privatisation of the postal savings system in last September's general election. A University of Cairo graduate in Egypt, she worked as an Arabic translator and television news presenter before going into politics. She dabbled with various parties before joining the LDP, having been affiliated with the Japan New Party, New Frontier Party, Liberal Party and New Conservative Party, all of which are now defunct.