The Japanese government has punished two big corporations implicated in the illegal sale of high-technology machinery to the Soviets -- but only after pressure from the Pentagon.

Tokyo was so afraid of hurting its lucrative trade ties to the United States that it secretly negotiated with the Pentagon and agreed on the punishment of the two Japanese firms in May to appease the U.S. government. The negotiations and agreement are spelled out in a Defense Department memorandum classified "secret."

The subject of the memorandum was the $17 million sale by Toshiba of sophisticated propeller-milling hardware that allowed the Soviets to make their submarines almost undetectable. It could cost American taxpayers $30 billion to overcome this tremendous technical advantage.

One page in the memo is subtitled "Sanctions Against C. Itoh," the huge trading company that handled the sale for Toshiba. In a series of columns, we have depicted C. Itoh as a culprit that escaped with a slap on the wrist: a three-month ban on Soviet deals.

Through its American representatives, C. Itoh has protested vociferously that the company didn't know what was in the crates Toshiba was shipping to the Soviets. The lobbying effort was led by Roderick Hills, who initially described himself as a "friend" of C. Itoh, but eventually felt obliged to register as a foreign agent for the company.

Hills correctly maintains that no publicly released U.S. or Japanese official report charges that C. Itoh knew what was in the Toshiba crates. But Hills tries to paint the three-month ban on deals with the Soviets as strictly a voluntary sacrifice by C. Itoh to help the Japanese government out of an "extremely embarrassing" fix.

The secret Pentagon memo doesn't put it quite that way. While it notes that Japanese trade officials believed "that there was no malicious intent on behalf of this major trading company," the memo then goes to the heart of the matter: "C. Itoh failed to inspect the merchandise itself, even though it acted as the formal exporter."

Instead of describing any voluntary action by the company, the secret memo refers to three actions to be taken "against C. Itoh" by the Japanese government after "extensive confidential negotiations." They are:

"After administering a 'heavy warning' and a public reprimand, {Japan} will prohibit exportation of all machine tools to {Soviet bloc} countries for three months."

"C. Itoh will be instructed to reform its internal procedures or face further punishment."

"C. Itoh will be required to report" detailed information on any machine-tool exports during the three-month ban.

"C. Itoh is one of Japan's largest trading companies," the memo notes, "and even a short ban involves very large amounts of money . . . . The important factor here is not the amount of money, but the social disgrace involved when C. Itoh becomes only the fourth offender in Japanese corporate history to have administrative sanctions applied to it."