Why Japan's history texts are volatile issue in S. Korea

South Koreans are in an uproar over the way in which new Japanese textbooks have revised the historical account of Japan's 36-year occupation of that country.

Around the country, senior citizens' groups have held anti-Japanese rallies.Security at the Japanese Embassy was tightened late last week when a male caller threatened to blow up the building. Another caller threatened to kill the Japanese ambassador to Korea, Toshikazu Maeda.

This furor comes at a time when the relationship between the two countries is particularly strained by recent negotiations on Seoul's bid for economic development loans from Tokyo. The original request has already been whittled from $6 billion to $4 billion with terms unacceptable to the Koreans.

It is doubtful that, in any military occupation, either side could produce a perfectly accurate record. However, the Koreans and many Westerners here agree that the Japanese were wrong in describing the invasion into Korea as an ''advance'' and the bloody nationwide March 1 Movement for independence in 1919 as a ''riot.''

But the passages of the new account that strike at the core of Korean pride are those dealing with the moves to ''Japanize'' the Korean Peninsula. Those moves occurred in the latter part of the occupation, which ended in 1945.

Koreans who lived through those days confirm that they were forbidden to speak Korean in public places, forced to take Japanese names, and required to worship at Shinto shrines. (Shinto was Japan's state religion prior to 1945.) The new textbooks merely suggest that such practices were encouraged by the Japanese authorities.

Besides the textbook issue, other recent incidents have angered the Koreans.

One is Japan's informal trade relations with North Korea. And Japan allows the presence of an association of pro-North Korean citizens. The government contends that infiltration by North Korean spies into the South is made easier by this relationship.

Also, in 1980, the Japanese-South Korean ties were strained by Japan's prime minister, who reportedly said Japan would reexamine its relationship with North Korea if South Korean dissident Kim Dae Jung was executed.

But this time the Koreans have found strange bedfellows in their communist neighbors, North Korea and China, who are also outraged by the revised historical account of their treatment by the Japanese. Unlike the Chinese, the Koreans did not make a formal protest but placed a request for an explanation through their embassy in Tokyo.

The Japanese response did not make any commitment to rewrite the historical accounts in question, but said, ''We fully understand the Korean people's feeling and intend to honor their opinions and criticism in a humble manner.'' The Korean government has taken this answer as an affirmative sign for correction of the textbook passages.

Political analysts say Seoul is cautious because it doesn't wish to upset the negotiations for Japanese loans to help finance projects in Korea's new five-year plan. Although the 14 months of talks were rescued by Korea agreeing to reduce the requested $6 billion to $4 billion in exchange for better terms, the situation remains tense.

The Japanese are prepared to offer only $1.5 billion in the attractive official development assistance loan instead of the Koreans' bid for at least $2 .3 billion in such loans. The remainder in either case would be in the form of Japanese Export-Import bank credits, which have more expensive strings attached.