French language on the photo. They did a European tour, including France, in 1921 (he was born in 1901).
The signatures don't look like others I found, but maybe they changed when he became emperor?
It makes sense that the photograph was taken in France in 1921 when Hirohito was on a European tour. Hirohito was formally proclaimed Crown Prince and heir apparent in 1916. He had also been decorated with the Grand Cordon of the Order of the Chrysanthemum after 1912 when his father became Emperor and he became her apparent. He is wearing the Grand Cordon of the Order of the Chrysanthemum in this photograph.
The lower part of his signature on this photograph does resemble the lower part of his signature as emperor. But who is the woman? According To what I have read, he married in 1924 for the first and only time. Princess Nagako married Crown Prince Hirohito on January 26, 1924 and became the Crown Princess of Japan. She became Empress Kōjun upon Hirohito's accession to the throne on December 25, 1926.
You may wish to post this image via asian art forum. There is a member there I. Nagi who is exceptional at reading Japanese calligraphy.
Upon further research, I found a 1930 news report: "Prince Takamatsu and wife Princess Kikuko Tokugawa aka Princess Takamatsu arriving at Paris Gare de Lyon for a stay in France, in May 1930 in Paris, France." And a photo (different image but same hat; and she is smiling) captioned: "Prince and Princess Takamatsu of Japan who have reached Paris on their way to London . The Prince is a brother of the Emperor . His wife before her marriage was Mlle . Kikuki Tokogawa , daughter of the well known prince of that name . 12 June 1930"
Thank you so much, Mark! And thank you for your extensive research. The signatures are alike - but not identical - to the ones on my photograph and are not in the same places, so I am confident that my photo was personally signed by both the Prince and Princess. I am listing it in my next five day eBay auction to be sold on Sat. May 1 (listed April 26th) with link in my Live! ad. It will be listed under [Hirohito] but their names will be in the description with starting price $20 with no reserve. Thanks again, Mark. And thanks again JK for your earlier reply.