A Spanish-Japanese War has been discussed on this site...a lot. As far as I know though, we don't have a timeline depicting one with much consideration, as it's usually a side-show in timelines with a different Europe and/or North America in the 19th century.
This is a challenge to create the most plausible timeline on the topic with a minimum of eight dates. The war itself must take place during the 1890s to 1920s. The rest of the world should stay relatively recognisable, but you can play around with relevant events like the Russo-Japanese, Sino-Japanese, and Spanish-American Wars obviously.