Nakasone: ambitious, outspoken

Yasuhiro Nakasone has had to overcome considerable ''image'' problems on the way to achieving his longstanding ambition to be Japan's prime minister.

The ruling Liberal Democratic Party normally chooses a leader it thinks can best mediate between the various rival factions to maintain party unity. Mr. Nakasone, however, for years has been the man everyone thought would one day become premier, but about whom many had various reservations.

The first stumbling block was his obvious driving ambition (considered to be un-Japanese), his seeming willingness to turn his back on friends to promote his political career, and his ability to switch direction - earning him the derogatory nickname of ''political weather vane.'' In conservative political circles, he has stood out for his showy behavior and outstanding oratorical skills.

Finally, he has had to overcome suspicions of involvement in the Lockheed bribery scandal of the mid-1970s. Nakasone went before the Diet (Parliament) to pledge his innocence, and no proceedings were ever instituted against him.

Born in Gumma prefecture, north of Tokyo, of a prosperous timber-merchant father and Christian mother, Nakasone graduated from the prestigious University of Tokyo and joined the powerful, now defunct Interior Ministry. Within a week, however, he enlisted in the Imperial Navy with Japan already at war. He rose to the rank of lieutenant commander in the paymaster corps, but never saw combat.

After the war, Nakasone returned to the Interior Ministry, inspecting local police forces, before deciding to go into politics. He won a parliamentary seat at the first attempt in 1947. In the Diet he quickly earned the reputation as an outspoken Young Turk always ready to challenge the political leadership of the day. At the young (for Japan) age of 41, he gained his first cabinet post in 1959 as director general of the Science and Technology Agency.

Eight years later, he came of age politically by assuming leadership of the small LDP faction led by his longtime mentor Ichiro Kono - immediately turning against the latter to support Kono's arch-rival, Eisaku Sato, for the premiership, and being rewarded with the post of transport minister.

This and subsequent zig-zags on major political issues to always be on the ''right side'' earned him his image of opportunism. For years Nakasone resented the ''weather vane'' taunt, but more recently has argued that ''the political world actually needs a meteorological station to forecast the weather'' (meaning someone able to forecast events and not get caught by surprise).

In the past 10 years, Nakasone gained experience in top posts as head of the Defense Agency and Ministry of International Trade and Industry. He has a reputation as a strong nationalist and a hawk on defense.

On his image as a ''spokesman of old-fashioned Japanese nationalism,'' he argues he merely wants to look out for Japan's best interests and is opposed to the prewar type of nationalistic state. ''People say I'm a hawk and a rightist, but it's not true. I'm a liberal who wants Japan to take a middle course by international standards.'' He insists he is not in favor of major rearmament of Japan, but would try to increase the defense budget to give the nation a capability to defend its own land and air space and secure vital sea lanes.

He has been suspected of being anti-American, but this seems to be based largely on criticisms of United States changeability on key issues (such as the Carter administration's vacillation over withdrawing US troops from South Korea, which Nakasone opposed). The new Japanese premier insists ''Japan needs a close and reliable friend for its continued security and (in this regard) the US-Japan relationship is vital.''

In domestic politics, he has pledged to continue outgoing Prime Minister Zenko Suzuki's movement for cheaper, smaller government.

He has been studying English conversation diligently, and the foreign statesmen who meet him will find Nakasone a more articulate and outspoken Japanese leader than they have been accustomed to.

In private life, the new premier relaxes by painting in oils. He is fond of old Japanese folk songs and composing traditional Japanese poems. He has one son and two daughters.