On July 27, 1853, the Tokugawa shogunate was in crisis. Shogun Tokugawa Ieyoshi passed away from what today is believed to be heat exhaustion at Edo Castle in the heart of Edo, present-day Tokyo.

Abe Masahiro, the top samurai bureaucrat under the shogun, had an urgent mission to carry out that day. He asked Tanaka Zenemon, an official from Saga, a feudal provincial government seat in today's Saga Prefecture, to come to Edo Castle.

Abe's urgent question: Could Saga manufacture about 200 iron cannons for the shogunate?