Tokyo — A leading public opinion poll posed the question: What would you do if Japan was invaded by a foreign power? An astonishing 44 percent of the Japanese respondents confessed they would run away or surrender, and the figure rose to 54 percent for youths between the ages of 15 and 24. Only 20.6 percent of those polled were willing to take up arms against the aggressors.
These figures should provide food for thought in Washington when the subject is raised of getting the Japanese to play a larger regional defense role.
Considering the results of the poll, the Yomiuri newspaper asked: ''Should we be happy that the no-war concept enunciated in our 'peace' Constitution has become so well rooted in the minds nf the Japanese? Or should we deplore these feckless descendants of erstwhile samurai who haven't got a modicum of spirit to fight for their country?''
It is against this lethargy that Prime Minister Yasuhiro Nakasone is now sounding a rallying call. It is an uphill battle against a deep underlying spirit of pacifism that has permeated postwar Japan.
Regular soundings by the prime minister's department, for example, find that just over half of the people consider themselves ''patriotic,'' but that spirit does not necessarily seem to be motivated by any determination to sacrifice self-interest for the national cause.
The most recent poll found 16 percent of respondents regarded themselves as ''very patriotic'' and another 36 percent ''more or less patriotic.'' But only 12 percent were ready to live up to the words of former US President John F. Kennedy, who counseled Americans, ''Ask not what your country can do for you. . . .''
Patriotism, anyway, has not been a very popular word in postwar Japan, being associated with the prewar military domination of national thought that proved so disastrous. The nation's surrender, with much of its capital burned to the ground and two other important cities atom-bombed out of existence, has left deep scars. Defending national honor with the sword was totally discredited in the public mind, which saw it only in terms of extreme poverty and starvation.
And this feeling lingers on. A recent detailed study by the Asahi newspaper found that the greatest number of people believe the experiences of World War II have contributed most to sustaining nearly 40 years of unbroken peace and prosperity.
The two other factors most often mentioned were the efforts of the people themselves to maintain peace and the postwar ''peace'' Constitution (which elements within the ruling Liberal Democratic Party would now like to change to give the military a freer hand).
A sobering point for the Reagan administration is that only a small number ( 14 percent) of the people polled considered that the US-Japan security treaty had played a significant role in securing peace.
But the most interesting aspect of the Asahi study was that the percentage of those citing the bad wartime experiences was highest among young people who were not even born then.
To look at the issue from another aspect: What is the greatest threat to Japan's security today? Prime Minister Nakasone, in a duet with Washington, says it is the threat of a Soviet attack.
But that is not a concept apparently shared by a vast majority of the Japanese public. A poll conducted late last year by the Japan Broadcasting Corporation (NHK) found that 54 percent of those polled believed the greatest security threat was posed by the US-Soviet arms expansion race.
Each respondent was allowed to pick more than one ''threat.'' Thirty-eight percent cited greater Japanese defense spending, 33 percent insufficient observance of the three nonnuclear principles (i.e., not to make, possess, or allow the entry into Japan of nuclear weapons).
Of some encouragement to the government was that 29 percent cited the poor public spirit toward the issue of defending the nation.
But only 27 percent shared Mr. Nakasone's fears of the Soviet threat.
Other aspects of the poll were that 28 percent favored strict neutrality as a government policy, while only 18 percent gave top priority to relations with the United States and 9 percent for solidarity with the Western bloc as a whole.
A number of respected observers believe such figures stem from the fact that the Japanese are only just beginning to emerge from a third phase of historic isolation. At the end of the Tokugawa era in the mid-19th century, Japan emerged from self-imposed isolation into a period of modernization and interaction with Western powers, particularly Britain and other European powers.
Then came a period of military adventurism in the 1930s and 1940s when the nation fell prey to a chauvinistic leadership. The military was able to gain ground because of the appalling poverty of rural districts which provided many recruits ready to listen to the expedient appeals of emperor and nation worship, subjugating the individual to the interests of the state.
When that proved a dead end, the postwar generation took up materialism as a national cause. The quality of life today is much better than it was in the 1940 s, '50s, and '60s. A lot of people do not want to destroy that by spending money on more tanks and planes, to turn Japan into an unsinkable aircraft carrier and risk annihilation under a rain of Soviet nuclear missiles in Siberia.
Older Japanese lament the alleged softness and selfishness of the postwar generation. The latter responds: ''Look where all your talk of patriotism and defending the nation has led us.''
Schools have done a lot to foster this spirit of pacifism. All passages considered likely to encourage a revival of militarism were excised from school textbooks during the American occupation and the left-wing teachers union (whose membership mainly supports the Socialist and Communist parties) has been extremely vigilant to see that things remain this way.
The Education Ministry thinks the time is certainly ripe to nurture in the classrooms ''the will to defend our country,'' but has so far made little headway on the highly emotional subject.
Most Japanese seem content at present to rely on the American security umbrella and a minimum of self-defense, and are far from convinced by Mr. Nakasone's arguments that ''it is a disgrace for any nation to rely on others for its national defense.'' Many think that Japan has prospered remarkably under the old system, so why change?
Most Japanese see the defense issue in terms of maintaining integrity as a middle-class, trading nation. There is little consensus beyond this.
Different regional concerns among the Japanese illustrate another reason for varying points of view on Japan's foreign policy. Such differences underscore the great difficulty any government in Tokyo has in promoting positive public sentiment on defense issues.