The editor of a Japanese women's magazine that gave a $1,000 gratuity intended for Nancy Reagan today showed The Washington Post a letter from the First Lady acknowledging a meeting with representatives of the magazine.

In an interview at his Tokyo Office, Tsugio Takamori, executive editor of Shufu no Tomo, dismissed a report in the Nov. 16 edition of The Washington Post quoting Mrs. Reagan as saying, through an aide, that she does not remember giving an interview to journalists from the magazine last January and had only a "faint recollection" of a brief photo session with them.

Takamori has said that he authorized the $1,000 thank-you fee for the interview. An envelope with the fee was found eight months later in a safe used by White House national security adviser Richard V. Allen.

The letter, addressed to Shufu no Tomo deputy editor Yoshiko Kimoto and signed "Nancy Reagan," said it was "a special pleasure to welcome" the three women sent by the magazine and thanked them for a "beautiful hand-painted stationery box" they presented to her.

White House deputy press secretary Larry Speakes said Mrs. Reagan had received a stationery box from the women and had written them a thank-you note. Although the letter and stationery box had not been mentioned in published accounts in Washington, Speakes gave an immediate, detailed response when questioned by a reporter.

Speakes said the hand-painted box, measuring 11 1/2 by 9 1/2 by 6 inches, was turned over to the White House archives the same day it was received and is kept in storage box number 71. He said the stationery box was assessed by Fisher Galleries in Washington as worth about $75.

Mrs. Reagan's letter was typewritten on stationery bearing the White House crest and dated May 7. It began: "It was a special pleasure to welcome you, Mrs. Takase and Miss Kamisaka, to the White House. You were among our first guests."

Kimoto accompanied Fuyuko Kamisaka, a free-lance writer who interviewed Mrs. Reagan at the White House on Jan. 21. The interview appeared in the March edition of Shufu no Tomo.

Chizuko Takase, who acted as interpreter for the session, is the wife of Tamotsu Takase, a Japanese professor and business consultant and a close friend of Allen. Mrs. Takase helped arrange the interview with Allen's help, according to Takamori.

A report appearing in today's evening edition of Asahi Shimbun, a major Japanese daily, said that Kamisaka had shown the letter addressed to Kimoto to a member of the newspaper's staff.

The newspaper reproduced a portion of the letter and quoted Kamisaka as saying that she had decided to disclose it to refute any allegations that she had not actually interviewed Mrs. Reagan.

Kamisaka said that she also had received a letter with the same wording from Mrs. Reagan and that both letters expressed gratitude for a handmade letterbox given her as a gift.

The newspaper quoted Kamisaka as saying that Allen said the $1,000 thank-you fee for Mrs. Reagan would be given to charity and that she had explained this point in her March article. In that article, however, she wrote only that she understood the money would be donated to charity through the White House.

Allen has said that he received the money and gave it to a secretary, who put it in an office safe and then forgot about it for eight months. The White House yesterday corrected an earlier statement saying that President Reagan had learned of the money found in Allen's safe only last Friday. In the revised version, White House spokesman David Gergen said that Reagan knew about the matter in September.

The letter received by Kimoto said, "I wish to thank you again for the beautiful hand-painted stationery box. Your thoughtful gesture of friendship and good will is very much appreciated." It went on to say, "The president joins me in sending you our best wishes. We hope that you enjoyed your visit to the United States."

White House spokesman Speakes has said that the January meeting with Mrs. Reagan lasted only about five minutes.

Kamisaka has asserted that she conducted an interview at the White House that lasted "at least 15 to 20 minutes."

According to Takamori, Kamisaka compiled her report from information she got directly from Mrs. Reagan during the Jan. 21 interview and responses received from the White House by telex after her return to Japan.

The questions for the interview with Mrs. Reagan, he said, had been submitted to the White House in advance in a letter written by Takase.

Takamori said that he did not know the source of the written answers and would have to check to see if a copy of the telex message still existed.

After consulting company accountants today, the editor said the magazine had received no receipt for the $1,000 thank-you fee -- in contrast, he said, to standard Japanese business customs.

Kimoto requested a receipt from the White House through Mrs. Takase, but the magazine had not to date received one, he said. Company expense records list the fee as $1,000 paid to Mrs. Reagan for charity, according to the editor.