Tokyo — Two names for Japan watchers to file away for the future: Shintaro Abe and Noboru Takeshita.
For the moment, the two are members of the newly formed Cabinet of Yasuhiro Nakasone, with Abe as foreign minister and Takeshita holding the finance portfolio.
But, assuming the ruling Liberal Democratic Party (LDP) does not disintegrate from factional differences and it retains power in the next general election, Abe and Takeshita will be leading candidates for the premiership in 1984.
Yet their emergence demonstrates the opposing forces that have eroded party unity for the past decade or more.Abe is heir apparent to the faction headed by former Prime Minister Takeo Fukuda. Takeshita is No. 3 in the group owing allegiance to Fukuda's most bitter political enemy, former Prime Minister Kakuei Tanaka.
The repeated political crises that have produced six different prime ministers in 12 years basically have stemmed from the Fukuda-Tanaka feud.
Abe already has had one try for the premiership, coming third in the four-man field headed by Nakasone in last month's biennial election for president of the ruling party. He was the only one of the defeated candidates to join the Nakasone Cabinet as the new prime minister sought to restore party unity and allay criticism of the continued domination by Tanaka and his supporters.
Both Abe and Takeshita are among the so-called ''new leaders'' of the LDP, the younger political generation taking Japan into the 1990s. Although only six years their senior, Nakasone is very much part - and, in fact, the last - of the ''older'' generation that has led the country since Mr. Tanaka was elected in 1972.
But in the political transition period now emerging, Tanaka's position paradoxically could be stronger than ever. Although he has been on trial for the past four years, charged with accepting bribes to promote Lockheed aircraft sales to Japan, Mr. Tanaka's political base has not diminished. It has broadened considerably.
Thus, it is very unclear whether a conviction and prison sentence would lead to his eclipse. For all its sophisticated surface veneer, Japanese politics retains a ''farm mentality.'' Of all the country's senior politicians, Tanaka - a self-made man without the educational credentials of Japan's elite - has the ''smell of the soil'' about him. This counts at election time - almost two-thirds of the LDP is returned by the rural farm vote.
Men like Nakasone, Abe, and Takeshita do not have this broad base of appeal. They cannot be elected purely by their own efforts. Thus, Takeshita, with Tanaka's backing, could have the edge when the LDP moves to select Nakasone's successor. (In view of the rapid demise of previous administrations, it is not premature to be talking in these terms.)
He was finance minister in the late 1970s and has served as chief cabinet secretary (chief confidant of the prime minister) to both Tanaka and the late Eisaku Sato, as well as holding the construction portfolio.
Abe is much more in the mold of the traditional elite who have ruled Japan. He is a graduate of the prestigious University of Tokyo, a journalist-turned-politican who has the added credential of being the son-in-law of Nobusuke Kishi, a staunchly pro-American prime minister in the early 1960s who is still active in politics.
Abe has previously been minister of agriculture and fisheries and minister of international trade and industry - both positions providing valuable diplomatic experience, especially in dealing with the United States. The Foreign Ministry is also a traditional stepping stone to the premiership.
Of his new position, Abe has said he will do his best to deepen a relationship of trust with the United States. He is also a strong supporter of the US-Japan defense relationship.
As far as defense issues are concerned, the US will also have to deal with Kazuo Tanikawa as director-general of the Defense Agency. An American-trained education expert, he is regarded as dovish on diplomatic and defense issues, counteracting his premier's hawkish image. He is fluent in English and has many friends in international circles.
The strategic (for American trade interests) post of international trade and industry has been given to Sadanori Yamanaka, an energetic, fast-thinking, and outspoken veteran politician who has served in the defense and environmental agency posts.
Then there is Iwazo Kaneko, the minister for agriculture and fisheries, who at 75 is holding only his second Cabinet post. His background, however, suggests he will staunchly defend Japanese farming interests against US pressure for further opening of the farm products market.