Two things the Japanese tried desperately to acquire during World War II were the blueprints for the jet fighter plane being developed by their German allies and the formula for penicillin being developed by their Allied enemies.

The Japanese wanted the secret of penicillin so badly they tried to steal it from the Soviet Union, with whom they still had diplopatic relations. The Japanese also sent agents to sift through the debris of a German laboratory outside Frankfurt that was attempting to make penicillin and which had just been bombed. The Japanese finally bought or stole some penicillin from a Spanish laboratory outside Barcelona in 1944.

These nuggets of fact are in once-secret documents just turned over to the National Archives by the National Security Agency, whose World War II predecessor broke the Japanese diplomatic code before the war began and systematically decoded Japanese cables throughout the war.

The importance the Japanese attached to acquiring the penicillin formula was underlined in a coded cable sent April 21, 1944 by Japan's foreign minister to his ambassador in Moscow. The cable read:

"The Soviet Union, England and America are manufacturing an extremely powerful drug called penicillin, which is making a tremendous contribution to the curing of wounded soldiers. The military authorities sent me word the other day that it is imperative that we get for them the best formula for the manufacture of this medicine.

"The Soviet Union is developing the product to a high degree of excellence," the cable went on. "Although I know it will be very difficult, I wonder if you could not secretly get me some data which would enable us to reproduce this product."

Japan was unsuccessful in acquiring penicillin secrets everywhere it tried until it turned to Spain, with whom it had friendly diplomatic relations through most of the war. On May 7, 1944, Japan's minister to Madrid cabled Tokyo that he had "obtained samples" of unrefined and refined penicillin from a laboratory in Barcelona.

"Together with research results," the ambassador cabled Tokyo, "I am sending these samples as soon as possible by submarine."

It is unclear from the documents whether Japan was able to profit from its penicillin coup, just as it is unclear what transpired from the Japanese attempts to secure the German blueprints for the jet fighter plane.

As early as Feb. 25, 1944, the Japanese military attache in Berlin cabled Tokyo that the Messerschmitt Co. was testing a jet fighter plane.

"It is of immediate importance that we negotiate an agreement with the Messerschmitt Co.," that cable said. "I have it from a secret source at Messerschmitt that the end of 1944 will see the appearance of a practical jet-propelled fighter."

Back came a cable from Tokyo that said: "Japan should dispatch technicians at once and begin the study of this plane while it is still experimental. Meanwhile, negotiate for the Messerschmitt plane or at least for the plans."

Barely one week later, the Japanese and Germans signed an agreement providing for a general exchange of patent rights concerning the "implements of war." But while negotiations continued and plans were made to take Messerschmitt engineers to Japan by submarine, it is never clear that even a prototype of the jet plane later built by Germany was ever built or tested by the Japanese.

One reason may have been that Japan could not afford to buy the German plane or even its plans. By April 1944, according to the documents released by the National Security Agency, Japan owed Germany $140 million in lend-lease funds that Germany insisted be paid off in 50 tons of gold.

By September, the Japanese were able to pay the Germans with six tons of gold they shipped secretly to Europe by submarine. But the prospects for the rest of the gold were slim. Said one cable from Tokyo to Berlin: "It is impossible to meet such a large demand."