In many English language texts the story is told that all the historical evidence collected by Higaonna Kanryo and Miyagi Chojun was destroyed during the Battle of Okinawa (April 1st - June 22nd 1945) - however, a slightly different story is told in this Chinese language text:
[空手] 吳賢貴 略傳[Empty-handed] A brief biography of Wu Xiangui
From what I can gather, this is a blog of a Taiwanese IOGKF practitioner who visited Okinawa and carried field research whilst training with the Goju Ryu instructors living on the island (I believe the Miyagi family). He has gathered photographs of 'Wu Xiangui' but this person still has no proper Chinese name (the characters used '吳賢貴' are Japanese phonetics)! However, at one point in the story relating the adventures of Miyagi Chojun and Wu Xiangui travelling to and from China - the author suddenly says this:
'It's a pity that the Chinese boxing books that were scheduled to be translated into Japanese were all burned in the US air raid on October 10, 1944.'
This devastating event was a full five months prior to the catastrophic Battle of Okinawa! Of course, there may have been more than one collection of historical data and this statement might only be referring to the gongfu manuals (common in China) that Miyagi Chojun was presented with by the Head Teachers working at the Jing Wu Athletic Association!