After the end of Russo-Japanese War Imperial Marine Association established a group called the Construction of the Imperial Volunteer Fleet /帝国義勇艦隊建設 - Teikoku Giyū Kantai Kensetsu/ in order to increase the strength of Japanese Imperial Navy. The main objective of this group was to help build auxiliary vessels that during peacetime would be used as commercial vessels but during times of war would be commissioned and outfitted with weapons.
Sakura Maru became the first such ship made. It was build by Mitsubishi Shipbuilding Yard in Kobe and launched on June 6, 1908. Mail and passenger express ship in times of peace - auxiliary cruiser in times of war.
According to the 1905 Imperial Volunteer Fleet founding documents:
1. Construction of the Imperial Volunteer Fleet is established to accept donations from all japanese male and female citizens.
2. Imperial Volunteer Fleet established to build vessels at the instruction of the appropriate government ministers.
3. Vessels of the Imperial Volunteer Fleet will be build within the Empire of Japan. However, when necessary, it is permitted to purchase vessels from other sources.
4. A committee to oversee the collected funds of the Imperial Volunteer Fleet is established.
5. The final goal will be to collect at least 15 000 000 yen.
6. Each donator will be awarded with a badge [of the the appropriate degree that corresponds to the amount donated] from the Chairman.
7. Those who donate more than 1000 yen will be awarded a Gold Merit Badge from the Chairman.
8. Funds collected for the Imperial Volunteer Fleet will not be used for any other purpose.
In total nine badges for donators were established.
The main manufacturer of these badges was Gyokuhō workshop in Tokyo.