WASHINGTON (AP) _ In the spring of 1971, national security adviser Henry Kissinger had an urgent need to see the U.S. ambassador to Pakistan, Joseph Farland, and asked the envoy to travel secretly to California for a rendezvous.

The issue was Kissinger's plan to make an unannounced trip to China as part of President Nixon's stealth program to reopen contacts with the communist country. Kissinger asked Farland to come up with a cover story so that his true mission to California would not be disclosed.

Farland's reply was creative, to say the least.

In a May 4 telegram to Kissinger, Farland said he was sending the following message to the State Department to explain his hastily arranged travel plans:

``Have received tentative purchase offer for family coal holdings; offer figure is in excess of $2 million. Various questions involved which cannot be handled telegraphically and timing major factor. Therefore request on most urgent basis departmental authority to travel to Hawaii or possibly West Coast at own repeat own expense for short meeting with lawyer and principal.''

The ruse worked. The two met, there was no leak about the encounter or other aspects about the opening to China, and Kissinger was able to go off on his trip to Beijing two months later, the rest of the world oblivious to his activities.

The Farland memo was among 100,000 pages of previously classified Nixon-era materials released Thursday by the National Archives. The materials cover the foreign policy issues that dominated the Nixon presidency, including China, Russia, Vietnam.

Nixon disclosed his China initiative in a dramatic announcement to the nation on July 15, 1971. He said Kissinger had just returned from Beijing after laying the groundwork for a presidential visit the following February.

The documents stress time and again the importance Kissinger attached to secrecy.

Four days before Nixon's announcement, Kissinger sent him a memo saying, ``They (the Chinese) will not understand even a minor leak and will consider it a deliberate affront and proof of unreliability. Please keep P.R. types ignorant. A leak or even a hint is certain to blow everything. I cannot be too strong on this.''

Kissinger went to China after a 10-day Asia tour that, according to the public announcement, was to have ended in Pakistan but actually wound up in China. No American official had set foot in China since 1949.

A classified State Department memo, dated June 4, outlined Kissinger's July 2-12 itinerary but left the identity of Kissinger's last stop deliberately vague. The announced stops were Saigon, Bangkok, New Delhi and Rawalpindi. The July 9-11 visit to China was simply listed in the memo as ``other site.''

When he arrived in China on July 9, Kissinger reported back to Nixon on his meeting that day with Premier Chou en-lai. A ``Top Secret/Sensitive/Exclusively Eyes Only'' memo for Nixon carried the following exchange:

Kissinger: The president asked that this mission be secret until after we meet, so we can meet unencumbered by bureaucracy, free of the past and with the greatest possible latitude.

Chou: You don't like bureaucracy either.

Kissinger: Yes, and it's mutual. The bureaucracy doesn't like me.