“It may be a mere historical footnote, but to this day a giant cannonball cast during this era remains on an obelisk at Ohato beside Nagasaki harbor.
“According to Plutschow, originally the gift of a Nagasaki merchant, the iron ball along with cannon was intended to be deployed against the rebel fortress at Shimabara*. Even so, the sheer size of this object (175cm circumference; 560kg weight) makes that assertion somewhat improbable.
“Whatever the provenance of the ‘Ohato cannonball’, it does testify to a transfer of casting techniques [and technology] probably from the Dutch and with the Ayama family of temple bell caster a likely candidate.”
– World Trade Systems of the East and West: Nagasaki and the Asian Bullion Trade Networks, by Geoffrey C. Gunri, 2017* During the Shimabara Rebellion (1637–1638), rebellious Christian peasants were besieged at Hara Castle. Following their defeat, and the subsequent suppression of Christianity in Japan, the Shogunate decided to expel the Catholic Portuguese – who had supported the peasants – from Japan. The Protestant Dutch, meanwhile, gained the trust of the authorities after they bombarded Hara Castle, where the insurgents had taken refuge, and thus gained a monopoly on European trade with Japan during the 214-year period of isolation known as sakoku [“closed country”] with the proviso that they conduct no evangelism.