Thanks to Daedala and Yune Kyung Lee. Published in Clarkesworld Magazine. Reprinted in The Year’s Best SF 18, ed. David G. Hartwell.
Warfare in a world where the calendar in use determines consensus reality, which in turn enables different exotic technologies, with a side helping of ethics.
For the curious, General Jedao’s tactics are based on Admiral Yi Sun-Shin’s tactics at the Battle of Myeongnyang during the Imjin War (cockamamie diagram at my Dreamwidth blog), although Jedao himself isn’t very much like Yi. Yi did better, by the way: he was outnumbered 10 to 1, and took even fewer losses, but I didn’t want to push suspension of disbelief too far.