This novel, just released by Fireship Press is set outside the time period for this site so I have not listed it, however, as the cover says, it is one of the very few novels that is set during the 1904-1905 Russo-Japanese War so it sounds interesting. [Edit: The book is now listed on the site]
"Paul Swinburne, a young naval officer, is court martialed; but he refuses to testify on his own behalf. No one knows why. As a result, he is dismissed from the Royal Navy; and his hopes and dreams are shattered-or are they?
The Japanese and the Russians are edging toward war, and the Japanese are sorely in need of trained naval officers. Swinburne is recruited and travels half-way around the world to fight for a country about which he knows little, and in a war about which he knows nothing. That, however, does not keep him from engaging in a series of breathtaking adventures and ultimately achieving great distinction.
Making this book even more interesting is that it is one of the very few novels that is set during the 1904-1905 Russo-Japanese War. Yet it was this war that established Japan as a serious military power in Asia; and, in effect, sewed the seeds for WW-II."