A new ''get tough'' policy is emerging in South Korean dealings with Japan.
Korea has a love-hate relationship with Japan. Koreans seek to emulate Japan's postwar economic success, but a recent opinion poll found the majority of them place it second only to North Korea among countries they most dislike.
Partly this stems from bitterness over Japanese occupation of the Korean Peninsula for most of the first half of this century, although there are more modern reasons, too.
President Chun Doo Hwan has urged his countrymen to ''stop complaining about the past and concentrate on the future.'' But at the same time, he wants the Japanese to realize they are dealing with a country of growing economic and political maturity, demanding equal treatment.
Diplomats in Seoul predict fundamental changes in the relationship between the two.
The postwar era can be divided into three parts. From 1945, when Japanese troops were ousted, until 1965, when diplomatic relations were restored, there were hostility.
For the next 14 years there was harmony. The late President Park Chung Hee and his key advisers were Japanese-educated, spoke Japanese, and looked to the former colonial power for vital cash and technology.
Now that Park is dead, history is being revised, and recently he has been reviled for his ''obsequiousness'' toward Japan, which some Koreans believe cost them a great deal.
Today there are new leaders in Seoul, called by some the ''Hangul (Korean language) group,'' who don't speak Japanese and have no close historical connections with Japan.
This new regime is more prickly. It displays fierce pride in Korea's economic achievements. It wants good relations with Japan, but sees no reason why it shouldn't be treated as an equal. And it is quick to detect any slights from Japan.
This aspect comes through loud and clear in Seoul's demand for $6 billion in Japanese aid over the next five years.
Japan immediately insisted the request was excessive, and it also reacted badly to Korean attempts to link the aid with its military security against North Korea.
Tokyo officials insisted there was no way Japan was going to provide overt or covert military aid to anyone.
Although in recent weeks the two sides have moved closer together, the whole issue still arouses indignation in many a Korean breast. Korean government sources insist that the Japanese government and press either misunderstood the aid request or are deliberately distorting it.
Said one: ''We are not asking for military aid. We certainly don't want to see a single Japanese soldier set foot on Korean soil ever again. And we are not going to use the money to buy weapons.
''We use the term security in its overall sense. We need the Japanese aid to help build new highways, bridges, dams, schools, hospitals, etc. Only by developing a strong economy can we be militarily secure.''
Another official explained: ''Our boys on the DMZ (demilitarized zone), and Americans, too, are holding back the advance of communism so that the Japanese can enjoy complete security to build up their economy and make bigger trade profits. Is it too much to ask them to contribute something toward the cost of that effort?''
Koreans point out that each year they put more than 30 percent of their national budget - 6 percent of their gross national product - for defense. Sounding very much like US officials, Koreans complain bitterly that Japan spends less than 1 percent of its own GNP, ''and the other 5 percent goes on making its export industries even stronger.''
Seeking to put the aid issue into perspective, Foreign Ministry sources point out that in the past 16 years Japan has made a total profit of some $20 billion in trade with South Korea.
In the same period, it has given the country $1.6 billion in official aid - averaging $100 million a year.
One highly emotional official burst out: ''For 16 years the Japanese have been siphoning off our lifeblood. Don't we have a right to demand some of it back?''
The Koreans blame American permissiveness for Japan's ''bad behavior'' on the trade, aid, and defense issues. Only Washington, it is argued, has the leverage and muscle to bring Tokyo back into line.
But an American source commented: ''While we might feel some sympathy, there's no way Washington would get caught in the middle of that one.''
Another reason for wanting the United States to put pressure on Japan to act more to the likes of Korea in the international arena is explained by one official this way: ''We are now coming up fast as an economic power, and some people talk of us as a 'second Japan.' In view of Japan's current bad reputation that makes me wince, even though it's probably meant as a compliment.
''Our fear is that the US and other countries will see us in this light. . . as another devil, another disruptive force on the horizon. . . rather than as a hardworking partner. Then, after us, there are other developing countries coming up who will suffer in the same way as the inevitable comparison is made with Japan.
''This is the biggest danger facing Korea, and we feel strongly that the US must do something (to control Japan) for the sake of others.''
Irritation over aid is exacerbated by the growing trade gap, which last year was $3 billion in Japan's favor (about 60 percent of Korea's total balance-of-payments deficit).
Japan is Korea's biggest supplier, but is second to the US as an export market. Seoul says it has tried repeatedly but failed to break down Japan's barriers to Korean products.
So if the trade gap can't be narrowed by Korea's selling more to Japan, then the country must import fewer Japanese goods.
A spokesman for the Ministry of Commerce and Industry concedes there is now a deliberate policy to switch import sources to the US and Western Europe.
But it isn't easy - ''Japan's close proximity gives it such a big advantage in lower transportation costs. Still, we are trying our best.''
Korean companies are also seeking technology from other sources, although they insist that one reason is that Japanese enterprises no longer want to help what they see as an emerging rival.
As the Korean economy and national pride grow apace, this kind of friction will likely increase in the years ahead, according to a number of diplomatic observers.