The following is from "Kings, Commoners and Knaves - Further Chess Explorations" by Edward Winter, noted chess writer.
"On 6 April, 1987 we had a lengthy telephone conversation with Olga Capablanca Clark and subsequently received the following letter:
28 April 1987
Dear Chess Friends,
Among the multitude of games played by my late husband, Jose Raul Capablanca, there is one that has never been published nor even seen by anyone except the three of us: Capablanca, Tartakower and myself.
In the years that I had known Capa he had never played in private, he had never practiced, nor even had a chess set at home. Ever so different from the chess masters all over the world!
There was, however, a very special occasion. It happened in Paris. I believe the year was 1938. We stayed in the Hotel Regina, Place Jeanne D'Arc, quite near the Louvre Museum. I had one of my frequent bad colds and stayed in bed to recuperate, when Savielly Tartakower, one of our good friends, came over for a visit. He stayed quite a while. Then suddenly he said to Capa: "I have a chess set with me. Why not play a game?"
Much to my astonishment, Capa smiled. "Why not? We are in good company." He grabbed some of the hotel stationery, a small table was moved close to my bed and the two masters sat down to play. How long the game lasted I couldn't quite tell, as here and there I slept a little. I remember Capa woke me up by gently touching my shoulder, to give me a few folded sheets of Regina stationery, on which he had written the score of Capa vs. Tartakower. Of course he won.
"Here is a present for you, cherie."
Gingerly I took the folded stationery. "But you know I don't understand a thing about chess."
Both he and Tartakower laughed good naturedly.
"Take it and hide it well. Some day in years to come it will buy you a beautiful bijou", Capa said. "Ever since I was a child everything I did was written down. And this is the only chess game that is only yours."
Anyone wishing to buy the Capablanca jewel, as he referred to it, should write as soon as possible to Mr. Edward Winter…The 30th of September would be the appropriate time-limit, as I have authorized him to receive the bids on my behalf. In view of the exceptional nature of the game and surrounding circumstances, no offer under $US 10,000 will be accepted.
With sincerest good wishes to all chess players in all lands.
(Signed)
Olga Capablanca Clark"
Aftermath:
No bids were received by the deadline, and the present whereabouts of the Capablanca-Tartakower game-score are unknown. Olga Capablanca died in the mid 1990s.
Seems remarkable to me that no bids were received for the game-score... especially considering that the score was actually written by Capa's own hand.