Sieuxerrian-Dayashinese Collaboration during the Pan-Septentrion War

Newspaper cartoon from 1910 showing the general feelings each nation held for each other at the time

During the Pan-Septentrion War, the Imperial State of Sieuxerr and the Empire of Dayashina cooperated numerous times. Many of these events were kept secret until the 1970s however the numerous Allied intelligence agencies had long been suspicious of the Sieuxerrian-Dayashinese relations during the war. All of these actions were justified under the Sieuxerrian-Dayashinese Treaty of Understanding and Friendship that was signed and ratified by both nations in 1925.

Background

Main article: Sieuxerr-Dayashina relations

Relations between the two nations was relatively well in the late 19th and early 20th centuries. Sieuxerr supported Dayashinese attempts to decolonized and increase its influence, as it would directly impact its nearby Casaterran rivals. Dayashina saw it as an advantageous relationship as well, with increased Sieuxerrian focus in Casaterran would force resources away from Hemithea allowing for a possibly easier expansion. Between the 1920s until the years before the outbreak of the PSW, Sieuxerr and Dayashina routinely exchanged military observers. Sieuxerr was greatly interested in Dayashinese carrier and carrier aircraft development while Dayashina was interested in anti-armor and motorization development. Both sides would greatly benefit from the exchanges, and by the mid-1930s before the war, a number of anti-aircraft guns and their designs were sold to Dayashina in exchange for the B5N torpedo bomber.

Under the terms of the Sieuxerrian-Dayashinese Treaty of Understanding and Friendship outlined the general agreement between the two nations to not interfere in each other's respective area of influences. Along with this agreement, Sieuxerr gave Dayashina docking rights to its bases in Îles de Lern. There also was a relaxing of prices and tariffs between the two nations, with Dayashina exporting raw silk, teas and clothing to Sieuxerr and Sieuxerr in turn exporting industrial machinery, coal, and finished products at reduced costs.

Tensions began to show by 1936 to 1937, however these would never amount to anything.

The war

Defection of the IDNS Yuna

Yukio Niishi Masayuki Ozawa